diff --git a/.github/actions/testing-setup/action.yml b/.github/actions/testing-setup/action.yml
deleted file mode 100644
index 60499d4be1..0000000000
--- a/.github/actions/testing-setup/action.yml
+++ /dev/null
@@ -1,45 +0,0 @@
-name: 'Build-.testing-prerequisites'
-description: 'Build pre-requisites for .testing including FMS and a symmetric MOM6 executable'
-inputs:
-  build_symmetric:
-    description: 'If true, will build the symmetric MOM6 executable'
-    required: false
-    default: 'true'
-runs:
-  using: 'composite'
-  steps:
-    - name: Git info
-      shell: bash
-      run: |
-        echo "::group::Git commit info"
-        echo "git log:"
-        git log | head -60
-        echo "::endgroup::"
-
-    - name: Env
-      shell: bash
-      run: |
-        echo "::group::Environment"
-        env
-        echo "::endgroup::"
-
-    - name: Compile FMS library
-      shell: bash
-      run: |
-        echo "::group::Compile FMS library"
-        cd .testing
-        REPORT_ERROR_LOGS=true make build/deps/lib/libFMS.a -s -j
-        echo "::endgroup::"
-
-    - name: Compile MOM6 in symmetric memory mode
-      shell: bash
-      run: |
-        echo "::group::Compile MOM6 in symmetric memory mode"
-        cd .testing
-        test ${{ inputs.build_symmetric }} == true && make build/symmetric/MOM6 -j
-        echo "::endgroup::"
-
-    - name: Set flags
-      shell: bash
-      run: |
-        echo "TIMEFORMAT=... completed in %lR  (user: %lU, sys: %lS)" >> $GITHUB_ENV
diff --git a/.github/workflows/verify-linux.yml b/.github/workflows/verify-linux.yml
index 146b4e6ab7..4c2817f4ee 100644
--- a/.github/workflows/verify-linux.yml
+++ b/.github/workflows/verify-linux.yml
@@ -2,8 +2,13 @@ name: Linux verification
 
 on: [push, pull_request]
 
+env:
+  MOM_TARGET_SLUG: ${{ github.repository }}
+  MOM_TARGET_LOCAL_BRANCH: ${{ github.base_ref }}
+
 jobs:
   # Documentation
+
   check-style-and-docstrings:
     runs-on: ubuntu-latest
 
@@ -38,34 +43,10 @@ jobs:
         cat all_errors
         test ! -s  all_errors
 
-  # Dependencies
-
-  build-fms:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - uses: ./.github/actions/ubuntu-setup/
-
-      - name: Build libFMS.a
-        run: make -C .testing build/deps/lib/libFMS.a -j
-
-      - name: Upload libFMS.a and dependencies
-        uses: actions/upload-artifact@v4
-        with:
-          name: fms-artifact
-          path: |
-            .testing/build/deps/include/
-            .testing/build/deps/lib/libFMS.a
-          retention-days: 1
-
   # Executables
 
   build-symmetric:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -74,25 +55,23 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 with symmetric indexing
-        run: |
-          make -C .testing build/symmetric/MOM6 -j \
-          -o build/deps/lib/libFMS.a
+        run: make -C .testing -j build/symmetric/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-symmetric.tar .testing/build/symmetric/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/MOM6
+          path: mom6-symmetric.tar
           retention-days: 1
 
   build-asymmetric:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -101,25 +80,23 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 with asymmetric indexing
-        run: |
-          make -C .testing build/asymmetric/MOM6 -j \
-          -o build/deps/lib/libFMS.a
+        run: make -C .testing -j build/asymmetric/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-asymmetric.tar .testing/build/asymmetric/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-asymmetric-artifact
-          path: .testing/build/asymmetric/MOM6
+          path: mom6-asymmetric.tar
           retention-days: 1
 
   build-repro:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -128,25 +105,23 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
-      - name: Compile repro
-        run: |
-          make -C .testing build/repro/MOM6 -j \
-          -o build/deps/lib/libFMS.a
+      - name: Compile MOM6 with bit-reproducible optimization
+        run: make -C .testing -j build/repro/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-repro.tar .testing/build/repro/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-repro-artifact
-          path: .testing/build/repro/MOM6
+          path: mom6-repro.tar
           retention-days: 1
 
   build-openmp:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -155,24 +130,24 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 supporting OpenMP
-        run: make -C .testing build/openmp/MOM6 -j -o build/deps/lib/libFMS.a
+        run: make -C .testing -j build/openmp/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-openmp.tar .testing/build/openmp/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-openmp-artifact
-          path: .testing/build/openmp/MOM6
+          path: mom6-openmp.tar
           retention-days: 1
 
   build-target:
     if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -181,28 +156,31 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile target FMS
+        run: |
+          make -C .testing \
+          DO_REGRESSION_TESTS=1 \
+          build/target_codebase
+          make -C .testing/build/target_codebase/.testing -j \
+          build/deps/lib/libFMS.a
 
       - name: Compile target MOM6
         run: |
-          make -C .testing build/target/MOM6 -j \
-          -o build/deps/lib/libFMS.a \
-          MOM_TARGET_SLUG=$GITHUB_REPOSITORY \
-          MOM_TARGET_LOCAL_BRANCH=$GITHUB_BASE_REF \
-          DO_REGRESSION_TESTS=True
+          make -C .testing -j \
+          DO_REGRESSION_TESTS=1 \
+          build/target/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-target.tar .testing/build/target/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-target-artifact
-          path: .testing/build/target/MOM6
+          path: mom6-target.tar
           retention-days: 1
 
   build-opt:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -211,39 +189,31 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
-      - name: Compile optimized model
-        run: |
-          make -C .testing build/opt/MOM6 -j \
-          -o build/deps/lib/libFMS.a
-
-      - uses: actions/upload-artifact@v4
-        with:
-          name: mom6-opt-artifact
-          path: .testing/build/opt/MOM6
-          retention-days: 1
+      - name: Compile MOM6 with aggressive optimization
+        run: make -C .testing -j build/opt/MOM6
 
       - name: Compile timing tests
+        run: make -C .testing build.timing
+
+      - name: Prepare artifact
         run: |
-          make -C .testing build.timing -j \
-          -o build/deps/lib/libFMS.a
+          tar -cf mom6-opt.tar \
+          --exclude='.testing/build/timing/time_*.o' \
+          .testing/build/opt/MOM6 \
+          .testing/build/timing/time_*
 
       - uses: actions/upload-artifact@v4
         with:
-          name: mom6-timing-artifact
-          path: |
-            .testing/build/timing/time_*
-            !.testing/build/timing/time_*.o
+          name: mom6-opt-artifact
+          path: mom6-opt.tar
           retention-days: 1
 
   build-opt-target:
     if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -252,44 +222,41 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile target FMS
+        run: |
+          make -C .testing \
+          DO_REGRESSION_TESTS=1 \
+          build/target_codebase
+          make -C .testing/build/target_codebase/.testing -j \
+          build/deps/lib/libFMS.a
 
       - name: Compile target MOM6
         run: |
-          make -C .testing build/opt_target/MOM6 -j \
-          -o build/deps/lib/libFMS.a \
-          MOM_TARGET_SLUG=$GITHUB_REPOSITORY \
-          MOM_TARGET_LOCAL_BRANCH=$GITHUB_BASE_REF \
-          DO_REGRESSION_TESTS=True
-
-      - uses: actions/upload-artifact@v4
-        with:
-          name: mom6-opt-target-artifact
-          path: .testing/build/opt_target/MOM6
-          retention-days: 1
+          make -C .testing -j \
+          DO_REGRESSION_TESTS=1 \
+          build/opt_target/MOM6
 
       - name: Compile target timing tests
         run: |
-          make -C .testing/build/target_codebase/.testing build.timing -j \
-          -o build/deps/lib/libFMS.a
-          MOM_TARGET_SLUG=$GITHUB_REPOSITORY \
-          MOM_TARGET_LOCAL_BRANCH=$GITHUB_BASE_REF \
-          DO_REGRESSION_TESTS=true
+          make -C .testing/build/target_codebase/.testing \
+          DO_REGRESSION_TESTS=1 \
+          build.timing
+
+      - name: Prepare artifact
+        run: |
+          tar -cf mom6-opt-target.tar \
+          --exclude='.testing/build/target_codebase/.testing/build/timing/time_*.o' \
+          .testing/build/opt_target/MOM6 \
+          .testing/build/target_codebase/.testing/build/timing/time_*
 
       - uses: actions/upload-artifact@v4
         with:
-          name: mom6-timing-target-artifact
-          path: |
-            .testing/build/target_codebase/.testing/build/timing/time_*
-            !.testing/build/target_codebase/.testing/build/timing/time_*.o
+          name: mom6-opt-target-artifact
+          path: mom6-opt-target.tar
           retention-days: 1
 
   build-coverage:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -298,35 +265,34 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 with code coverage
-        run: make -C .testing build/cov/MOM6 -j -o build/deps/lib/libFMS.a
+        run: make -C .testing -j build/cov/MOM6
 
       - name: Compile MOM6 unit tests
         run: |
-          make -C .testing build/unit/test_MOM_file_parser -j \
-          -o build/deps/lib/libFMS.a
-          make -C .testing build.unit -j \
-          -o build/deps/lib/libFMS.a
+          make -C .testing -j build/unit/test_MOM_file_parser
+          make -C .testing -j build.unit
+
+      - name: Prepare artifact
+        run: |
+          tar -cf mom6-coverage.tar \
+          --exclude='.testing/build/unit/test_*.o' \
+          .testing/build/cov/MOM6 \
+          .testing/build/cov/*.gcno \
+          .testing/build/unit/test_* \
+          .testing/build/unit/*.gcno
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-coverage-artifact
-          path: |
-            .testing/build/cov/MOM6
-            .testing/build/cov/*.gcno
-            .testing/build/unit/test_*
-            .testing/build/unit/*.gcno
-            !.testing/build/unit/test_*.o
+          path: mom6-coverage.tar
           retention-days: 1
 
   build-coupled-api:
     runs-on: ubuntu-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -335,17 +301,13 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 for the GFDL coupled driver
-        run: |
-          make -C .testing check_mom6_api_coupled -j \
-          -o build/deps/lib/libFMS.a
+        run: make -C .testing -j check_mom6_api_coupled
 
-  #---
+  # Tests
 
   test-grid:
     runs-on: ubuntu-latest
@@ -364,19 +326,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download asymmetric MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-asymmetric-artifact
-          path: .testing/build/asymmetric/
 
-      - name: Verify symmetric-asymmetric grid invariance
+      - name: Unpack artifacts
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/asymmetric/MOM6
-          make -C .testing test.grid -o build/symmetric/MOM6 -o build/asymmetric/MOM6
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-asymmetric.tar
+
+      - name: Run grid verification test
+        run: |
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          -o build/asymmetric/MOM6 \
+          test.grid
 
   test-layout:
     runs-on: ubuntu-latest
@@ -393,12 +359,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify processor domain layout
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
+
+      - name: Run layout test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.layout -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.layout
 
   test-rotate:
     runs-on: ubuntu-latest
@@ -415,12 +384,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify rotational invariance
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
+
+      - name: Run rotation test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.rotate -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.rotate
 
   test-restart:
     runs-on: ubuntu-latest
@@ -437,58 +409,17 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify restart invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.restart -o build/symmetric/MOM6
 
-  test-nan:
-    runs-on: ubuntu-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
 
-      - uses: ./.github/actions/ubuntu-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify aggressive initialization
+      - name: Run restart test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.nan -o build/symmetric/MOM6
-
-  test-dim-t:
-    runs-on: ubuntu-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/ubuntu-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify time dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.t -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.restart
 
-  test-dim-l:
+  test-nan:
     runs-on: ubuntu-latest
     needs: build-symmetric
 
@@ -503,60 +434,29 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify horizontal length dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.l -o build/symmetric/MOM6
 
-  test-dim-h:
-    runs-on: ubuntu-latest
-    needs: build-symmetric
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
 
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/ubuntu-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify vertical thickness dimensional invariance
+      - name: Run NaN initialization test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.h -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.nan
 
-  test-dim-z:
+  test-dim:
     runs-on: ubuntu-latest
     needs: build-symmetric
 
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/ubuntu-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify vertical coordinate dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.z -o build/symmetric/MOM6
-
-  test-dim-q:
-    runs-on: ubuntu-latest
-    needs: build-symmetric
+    strategy:
+      matrix:
+        dim:
+          - {id: t, desc: "time"}
+          - {id: l, desc: "horizontal length"}
+          - {id: h, desc: "vertical thickness"}
+          - {id: z, desc: "vertical coordinate"}
+          - {id: q, desc: "enthalpy"}
+          - {id: r, desc: "density"}
 
     steps:
       - uses: actions/checkout@v4
@@ -565,38 +465,19 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup
 
-      - name: Download Artifacts
+      - name: Download symmetric MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify heat dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.z -o build/symmetric/MOM6
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
 
-  test-dim-r:
-    runs-on: ubuntu-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/ubuntu-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify density dimensional invariance
+      - name: Run ${{ matrix.dim.desc }} dimension test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.r -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.dim.${{ matrix.dim.id }}
 
   test-openmp:
     runs-on: ubuntu-latest
@@ -615,19 +496,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download OpenMP MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-openmp-artifact
-          path: .testing/build/openmp/
 
-      - name: Verify OpenMP invariance
+      - name: Unpack artifacts
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/openmp/MOM6
-          make -C .testing test.openmp -o build/symmetric/MOM6 -o build/openmp/MOM6
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-openmp.tar
+
+      - name: Run OpenMP test
+        run: |
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          -o build/openmp/MOM6 \
+          test.openmp
 
   test-repro:
     runs-on: ubuntu-latest
@@ -646,21 +531,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download REPRO MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-repro-artifact
-          path: .testing/build/repro/
+
+      - name: Unpack artifacts
+        run: |
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-repro.tar
 
       - name: Verify REPRO equivalence
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/repro/MOM6
-          make -C .testing test.repro \
+          make -C .testing -j \
           -o build/symmetric/MOM6 \
-          -o build/repro/MOM6
+          -o build/repro/MOM6 \
+          test.repro
 
   test-regression:
     if: github.event_name == 'pull_request'
@@ -680,22 +567,24 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download target MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-target-artifact
-          path: .testing/build/target/
+
+      - name: Unpack artifacts
+        run: |
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-target.tar
 
       - name: Check for regressions
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/target/MOM6
-          make -C .testing test.regression \
+          make -C .testing -j \
           -o build/symmetric/MOM6 \
           -o build/target/MOM6 \
-          DO_REGRESSION_TESTS=true
+          DO_REGRESSION_TESTS=1 \
+          test.regression
 
   run-coverage:
     runs-on: ubuntu-latest
@@ -712,29 +601,31 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-coverage-artifact
-          path: .testing/build/
+
+      - name: Unpack artifacts
+        run: |
+          tar -xpvf mom6-coverage.tar
+          find .testing/build/cov -name "*.gcno" -exec touch {} \;
+          find .testing/build/unit -name "*.gcno" -exec touch {} \;
 
       - name: Generate MOM6 coverage
         run: |
-          chmod u+rx .testing/build/cov/MOM6
-          make -C .testing -j run.cov \
-          -o build/cov/MOM6
+          make -C .testing -j \
+          -o build/cov/MOM6 \
+          run.cov
 
       - name: Generate unit test coverage
         run: |
-          EXECS=`find .testing/build/unit -regextype sed -regex ".*/test_[A-Za-z0-9_]*"`
-          chmod u+rx $EXECS
-          EXECS=`find .testing/build/unit -regextype sed -regex ".*/test_[A-Za-z0-9_]*" | sed 's:.testing/::'`
-          make -C .testing -j run.cov.unit \
-          $( for f in $EXECS; do echo "-o $f" ; done )
+          cd .testing && make -j \
+          $(for f in build/unit/test_*; do echo "-o $f"; done) \
+          run.cov.unit
 
       - name: Report coverage to CI
         run: |
-          make -C .testing report.cov \
-          -o build/cov/MOM6
-          EXECS=`find .testing/build/unit -regextype sed -regex ".*/test_[A-Za-z0-9_]*" | sed 's:.testing/::'`
-          make -C .testing report.cov.unit \
-          $( for f in $EXECS; do echo "-o $f" ; done )
+          cd .testing && make \
+          -o build/cov/MOM6 \
+          $(for f in build/unit/test_*; do echo "-o $f"; done) \
+          report.cov report.cov.unit
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
@@ -755,20 +646,19 @@ jobs:
       - name: Download timing tests
         uses: actions/download-artifact@v4
         with:
-          name: mom6-timing-artifact
-          path: .testing/build/timing/
+          name: mom6-opt-artifact
+
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-opt.tar
 
       - name: Run unit test timings
         run: |
-          chmod u+rx .testing/build/timing/time_*
-          EXECS=`cd .testing ; find build/timing -regextype sed -regex ".*/time_[A-Za-z0-9_]*"`
-          make -C .testing run.timing -j \
-          $( for f in $EXECS; do echo "-o $f" ; done )
+          cd .testing && make -j \
+          $(for f in build/timing/time_*; do echo "-o $f"; done) \
+          run.timing
 
       - name: Show timing results
-        run: |
-          make -C .testing show.timing \
-          DO_REGRESSION_TESTS=true
+        run: make -C .testing show.timing
 
   # These are most likely nonsense on a GitHub node, but someday it could work.
   compare-timings:
@@ -785,81 +675,71 @@ jobs:
 
       - uses: ./.github/actions/ubuntu-setup
 
+        # NOTE: This needs to occur before the artifacts are unpacked, because
+        #   our rule for setting up `target_codebase` depends on its presence,
+        #   rather than its contents.
+        # If we can improve this rule, then this can be moved after unpacking.
+      - name: Re-clone target directory
+        run: |
+          make -C .testing \
+          DO_REGRESSION_TESTS=1 \
+          build/target_codebase
+
       - name: Download optimized MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-opt-artifact
-          path: .testing/build/opt/
 
       - name: Download optimized target MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-opt-target-artifact
-          path: .testing/build/opt_target/
 
-        # TODO: Move f90nml and chmod setup to another step?
+      - name: Unpack artifacts
+        run: |
+            tar -xpvf mom6-opt.tar
+            tar -xpvf mom6-opt-target.tar
+
+      - name: Install preprocessor dependency
+        run: pip install f90nml
+
       - name: Profile with FMS clocks
         run: |
-          pip install f90nml
-          chmod u+rx .testing/build/opt/MOM6
-          chmod u+rx .testing/build/opt_target/MOM6
-          make -C .testing profile -j \
+          make -C .testing -j \
           -o build/opt/MOM6 \
           -o build/opt_target/MOM6 \
-          DO_REGRESSION_TESTS=true
+          profile
 
       - name: Profile with perf
         run: |
           sudo sysctl -w kernel.perf_event_paranoid=2
-          make -C .testing perf -j \
+          make -C .testing -j \
           -o build/opt/MOM6 \
           -o build/opt_target/MOM6 \
-          DO_REGRESSION_TESTS=true
-
-      # Collapse run.timing run.timing_target and show.timing into one rule
-      # TODO: Should this be a separate thing?
-
-      - name: Download timing tests
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-timing-artifact
-          path: .testing/build/timing/
+          perf
 
-      - name: Run timing tests
+      - name: Run unit test timings
         run: |
-          chmod u+rx .testing/build/timing/time_*
-          EXECS=`cd .testing ; find build/timing -regextype sed -regex ".*/time_[A-Za-z0-9_]*"`
-          make -C .testing run.timing -j \
-          $( for f in $EXECS; do echo "-o $f" ; done )
+          cd .testing && make -j \
+          $(for f in build/timing/time_*; do echo "-o $f"; done) \
+          run.timing
 
       - name: Show timing results
-        run: |
-          make -C .testing show.timing \
-          DO_REGRESSION_TESTS=true
-
-      - name: Re-clone target directory
-        run: |
-          make -C .testing build/target_codebase \
-          DO_REGRESSION_TESTS=True
-
-      - name: Download target timing tests
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-timing-target-artifact
-          path: .testing/build/target_codebase/.testing/build/timing/
+        run: make -C .testing DO_REGRESSION_TESTS=1 show.timing
 
       - name: Run target timing tests
         run: |
-          cd .testing/build/target_codebase/
-          chmod u+rx .testing/build/timing/time_*
-          EXECS=`cd .testing ; find build/timing -regextype sed -regex ".*/time_[A-Za-z0-9_]*"`
-          make -C .testing run.timing -j \
-          $( for f in $EXECS; do echo "-o $f" ; done )
+          cd .testing/build/target_codebase/.testing && make -j \
+          $(for f in build/timing/time_*; do echo "-o $f"; done) \
+          run.timing
 
       - name: Compare unit test timings
         run: |
-          make -C .testing compare.timing \
-          DO_REGRESSION_TESTS=true
+          make -C .testing \
+          DO_REGRESSION_TESTS=1 \
+          compare.timing
+
+  # Cleanup
 
   cleanup-common:
     runs-on: ubuntu-latest
@@ -875,7 +755,6 @@ jobs:
       - uses: geekyeggo/delete-artifact@v5
         with:
           name: |
-            fms-artifact
             mom6-asymmetric-artifact
             mom6-openmp-artifact
             mom6-repro-artifact
@@ -894,12 +773,7 @@ jobs:
       - test-rotate
       - test-restart
       - test-nan
-      - test-dim-t
-      - test-dim-l
-      - test-dim-h
-      - test-dim-z
-      - test-dim-q
-      - test-dim-r
+      - test-dim
       - test-grid
       - test-openmp
       - test-repro
@@ -910,7 +784,7 @@ jobs:
         with:
           name: |
             mom6-symmetric-artifact
-            mom6-timing-artifact
+            mom6-opt-artifact
 
   cleanup-pr:
     if: github.event_name == 'pull_request'
@@ -922,12 +796,7 @@ jobs:
       - test-rotate
       - test-restart
       - test-nan
-      - test-dim-t
-      - test-dim-l
-      - test-dim-h
-      - test-dim-z
-      - test-dim-q
-      - test-dim-r
+      - test-dim
       - test-grid
       - test-openmp
       - test-repro
@@ -942,5 +811,3 @@ jobs:
             mom6-target-artifact
             mom6-opt-artifact
             mom6-opt-target-artifact
-            mom6-timing-artifact
-            mom6-timing-target-artifact
diff --git a/.github/workflows/verify-macos.yml b/.github/workflows/verify-macos.yml
index 790cac3e52..d058336053 100644
--- a/.github/workflows/verify-macos.yml
+++ b/.github/workflows/verify-macos.yml
@@ -5,33 +5,14 @@ on: [push, pull_request]
 env:
   CC: gcc
   FC: gfortran
+  MOM_TARGET_SLUG: ${{ github.repository }}
+  MOM_TARGET_LOCAL_BRANCH: ${{ github.base_ref }}
 
 jobs:
-  # Dependencies
-  build-fms:
-    runs-on: macOS-latest
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - uses: ./.github/actions/macos-setup/
-
-      - name: Build libFMS.a
-        run: make -C .testing build/deps/lib/libFMS.a -j
-
-      - name: Upload libFMS.a and dependencies
-        uses: actions/upload-artifact@v4
-        with:
-          name: fms-artifact
-          path: |
-            .testing/build/deps/include/
-            .testing/build/deps/lib/libFMS.a
-          retention-days: 1
+  # Executables
 
   build-symmetric:
     runs-on: macOS-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -40,24 +21,23 @@ jobs:
 
       - uses: ./.github/actions/macos-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
-      - name: Compile symmetric index layout
-        run: |
-          make -C .testing build/symmetric/MOM6 -j -o build/deps/lib/libFMS.a
+      - name: Compile MOM6 with symmetric indexing
+        run: make -C .testing -j build/symmetric/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-symmetric.tar .testing/build/symmetric/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/MOM6
+          path: mom6-symmetric.tar
           retention-days: 1
 
   build-asymmetric:
     runs-on: macOS-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -66,24 +46,23 @@ jobs:
 
       - uses: ./.github/actions/macos-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
-      - name: Compile asymmetric index layout
-        run: |
-          make -C .testing build/asymmetric/MOM6 -j -o build/deps/lib/libFMS.a
+      - name: Compile MOM6 with asymmetric indexing
+        run: make -C .testing -j build/asymmetric/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-asymmetric.tar .testing/build/asymmetric/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-asymmetric-artifact
-          path: .testing/build/asymmetric/MOM6
+          path: mom6-asymmetric.tar
           retention-days: 1
 
   build-repro:
     runs-on: macOS-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -92,23 +71,23 @@ jobs:
 
       - uses: ./.github/actions/macos-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
+
+      - name: Compile MOM6 with bit-reproducible optimization
+        run: make -C .testing -j build/repro/MOM6
 
-      - name: Compile repro
-        run: make -C .testing build/repro/MOM6 -j -o build/deps/lib/libFMS.a
+      - name: Prepare artifact
+        run: tar -cf mom6-repro.tar .testing/build/repro/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-repro-artifact
-          path: .testing/build/repro/MOM6
+          path: mom6-repro.tar
           retention-days: 1
 
   build-openmp:
     runs-on: macOS-latest
-    needs: build-fms
 
     steps:
       - uses: actions/checkout@v4
@@ -117,24 +96,24 @@ jobs:
 
       - uses: ./.github/actions/macos-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile FMS
+        run: make -C .testing -j build/deps/lib/libFMS.a
 
       - name: Compile MOM6 supporting OpenMP
-        run: make -C .testing build/openmp/MOM6 -j -o build/symmetric/Makefile
+        run: make -C .testing -j build/openmp/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-openmp.tar .testing/build/openmp/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-openmp-artifact
-          path: .testing/build/openmp/MOM6
+          path: mom6-openmp.tar
           retention-days: 1
 
   build-target:
     if: github.event_name == 'pull_request'
-    runs-on: macos-latest
-    needs: build-fms
+    runs-on: macOS-latest
 
     steps:
       - uses: actions/checkout@v4
@@ -143,26 +122,30 @@ jobs:
 
       - uses: ./.github/actions/macos-setup/
 
-      - uses: actions/download-artifact@v4
-        with:
-          name: fms-artifact
-          path: .testing/build/deps/
+      - name: Compile target FMS
+        run: |
+          make -C .testing \
+          DO_REGRESSION_TESTS=1 \
+          build/target_codebase
+          make -C .testing/build/target_codebase/.testing -j \
+          build/deps/lib/libFMS.a
 
       - name: Compile target MOM6
         run: |
-          make -C .testing build/target/MOM6 -j \
-          -o build/deps/lib/libFMS.a \
-          MOM_TARGET_SLUG=$GITHUB_REPOSITORY \
-          MOM_TARGET_LOCAL_BRANCH=$GITHUB_BASE_REF \
-          DO_REGRESSION_TESTS=True
+          make -C .testing -j \
+          DO_REGRESSION_TESTS=1 \
+          build/target/MOM6
+
+      - name: Prepare artifact
+        run: tar -cf mom6-target.tar .testing/build/target/MOM6
 
       - uses: actions/upload-artifact@v4
         with:
           name: mom6-target-artifact
-          path: .testing/build/target/MOM6
+          path: mom6-target.tar
           retention-days: 1
 
-  #---
+  # Tests
 
   test-grid:
     runs-on: macOS-latest
@@ -181,21 +164,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download asymmetric MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-asymmetric-artifact
-          path: .testing/build/asymmetric/
 
-      - name: Verify symmetric-asymmetric grid invariance
+      - name: Unpack artifacts
+        run: |
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-asymmetric.tar
+
+      - name: Run grid verification test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/asymmetric/MOM6
-          make -C .testing -k test.grid \
+          make -C .testing -j \
           -o build/symmetric/MOM6 \
-          -o build/asymmetric/MOM6
+          -o build/asymmetric/MOM6 \
+          test.grid
 
   test-layout:
     runs-on: macOS-latest
@@ -212,13 +197,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify processor domain layout
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
+
+      - name: Run layout test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing -k test.layout \
-          -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.layout
 
   test-rotate:
     runs-on: macOS-latest
@@ -235,12 +222,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify rotational invariance
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
+
+      - name: Run rotation test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing -k test.rotate -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.rotate
 
   test-restart:
     runs-on: macOS-latest
@@ -257,12 +247,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify restart invariance
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
+
+      - name: Run restart test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing -k test.restart -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.restart
 
   test-nan:
     runs-on: macOS-latest
@@ -279,104 +272,29 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify aggressive initialization
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing -k test.nan -o build/symmetric/MOM6
-
-  test-dim-t:
-    runs-on: macos-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/macos-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify time dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.t -o build/symmetric/MOM6
 
-  test-dim-l:
-    runs-on: macos-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/macos-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify horizontal length dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.l -o build/symmetric/MOM6
-
-  test-dim-h:
-    runs-on: macos-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/macos-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
 
-      - name: Verify vertical thickness dimensional invariance
+      - name: Run NaN initialization test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.h -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.nan
 
-  test-dim-z:
-    runs-on: macos-latest
+  test-dim:
+    runs-on: macOS-latest
     needs: build-symmetric
 
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/macos-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify vertical coordinate dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.z -o build/symmetric/MOM6
-
-  test-dim-q:
-    runs-on: macos-latest
-    needs: build-symmetric
+    strategy:
+      matrix:
+        dim:
+          - {id: t, desc: "time"}
+          - {id: l, desc: "horizontal length"}
+          - {id: h, desc: "vertical thickness"}
+          - {id: z, desc: "vertical coordinate"}
+          - {id: q, desc: "enthalpy"}
+          - {id: r, desc: "density"}
 
     steps:
       - uses: actions/checkout@v4
@@ -385,38 +303,19 @@ jobs:
 
       - uses: ./.github/actions/macos-setup
 
-      - name: Download Artifacts
+      - name: Download symmetric MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
-      - name: Verify heat dimensional invariance
-        run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.z -o build/symmetric/MOM6
+      - name: Unpack artifacts
+        run: tar -xpvf mom6-symmetric.tar
 
-  test-dim-r:
-    runs-on: macos-latest
-    needs: build-symmetric
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: ./.github/actions/macos-setup
-
-      - name: Download Artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
-
-      - name: Verify density dimensional invariance
+      - name: Run ${{ matrix.dim.desc }} dimension test
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          make -C .testing test.dim.r -o build/symmetric/MOM6
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          test.dim.${{ matrix.dim.id }}
 
   test-openmp:
     runs-on: macOS-latest
@@ -435,19 +334,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download OpenMP MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-openmp-artifact
-          path: .testing/build/openmp/
 
-      - name: Verify OpenMP invariance
+      - name: Unpack artifacts
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/openmp/MOM6
-          make -C .testing -k test.openmp -k -o build/symmetric/MOM6 -o build/openmp/MOM6
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-openmp.tar
+
+      - name: Run OpenMP test
+        run: |
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          -o build/openmp/MOM6 \
+          test.openmp
 
   test-repro:
     runs-on: macOS-latest
@@ -466,19 +369,23 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download REPRO MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-repro-artifact
-          path: .testing/build/repro/
 
-      - name: Verify optimized equivalence
+      - name: Unpack artifacts
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/repro/MOM6
-          make -C .testing -k test.repro -o build/symmetric/MOM6 -o build/repro/MOM6
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-repro.tar
+
+      - name: Verify REPRO equivalence
+        run: |
+          make -C .testing -j \
+          -o build/symmetric/MOM6 \
+          -o build/repro/MOM6 \
+          test.repro
 
   test-regression:
     if: github.event_name == 'pull_request'
@@ -498,45 +405,91 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: mom6-symmetric-artifact
-          path: .testing/build/symmetric/
 
       - name: Download target MOM6
         uses: actions/download-artifact@v4
         with:
           name: mom6-target-artifact
-          path: .testing/build/target/
+
+      - name: Unpack artifacts
+        run: |
+          tar -xpvf mom6-symmetric.tar
+          tar -xpvf mom6-target.tar
 
       - name: Check for regressions
         run: |
-          chmod u+rx .testing/build/symmetric/MOM6
-          chmod u+rx .testing/build/target/MOM6
-          make -C .testing test.regression \
+          make -C .testing -j \
           -o build/symmetric/MOM6 \
           -o build/target/MOM6 \
-          DO_REGRESSION_TESTS=true
+          DO_REGRESSION_TESTS=1 \
+          test.regression
+
+  # Cleanup
+
+  cleanup-common:
+    runs-on: macOS-latest
+    permissions:
+      id-token: write
+    needs:
+      - test-grid
+      - test-openmp
+      - test-repro
+
+    steps:
+      - uses: geekyeggo/delete-artifact@v5
+        with:
+          name: |
+            mom6-asymmetric-artifact
+            mom6-openmp-artifact
+            mom6-repro-artifact
+            mom6-coverage-artifact
+
+  # NOTE: There is no way to conditionally define the elements in `needs`.
+  #   For now, we must create separate rules for each case.
 
-  cleanup:
-    runs-on: macos-latest
+  cleanup-push:
+    if: github.event_name != 'pull_request'
+    runs-on: macOS-latest
     permissions:
       id-token: write
     needs:
+      - test-layout
+      - test-rotate
+      - test-restart
+      - test-nan
+      - test-dim
       - test-grid
+      - test-openmp
+      - test-repro
+
+    steps:
+      - uses: geekyeggo/delete-artifact@v5
+        with:
+          name: |
+            mom6-symmetric-artifact
+            mom6-opt-artifact
+
+  cleanup-pr:
+    if: github.event_name == 'pull_request'
+    runs-on: macOS-latest
+    permissions:
+      id-token: write
+    needs:
       - test-layout
       - test-rotate
       - test-restart
       - test-nan
-      - test-dim-t
-      - test-dim-l
-      - test-dim-h
-      - test-dim-z
-      - test-dim-q
-      - test-dim-r
+      - test-dim
+      - test-grid
       - test-openmp
       - test-repro
+      - test-regression
 
     steps:
       - uses: geekyeggo/delete-artifact@v5
         with:
           name: |
-            fms-artifact
-            mom6-*-artifact
+            mom6-symmetric-artifact
+            mom6-target-artifact
+            mom6-opt-artifact
+            mom6-opt-target-artifact
diff --git a/.testing/Makefile b/.testing/Makefile
index ec6e5d1075..f5f6e9b1cd 100644
--- a/.testing/Makefile
+++ b/.testing/Makefile
@@ -213,10 +213,8 @@ endif
 
 ## Rules
 
-.PHONY: all build.regressions build.prof
+.PHONY: all
 all: $(foreach b,$(EXECS),$(BUILD)/$(b))
-build.regressions: $(foreach b,symmetric target,$(BUILD)/$(b)/MOM6)
-build.prof: $(foreach b,opt opt_target,$(BUILD)/$(b)/MOM6)
 
 # Executable
 .PRECIOUS: $(foreach b,$(EXECS),$(BUILD)/$(b))
@@ -230,7 +228,7 @@ LDFLAGS_DEPS = -L$(abspath $(DEPS)/lib)
 PATH_DEPS = PATH="${PATH}:$(abspath $(DEPS)/bin)"
 
 
-# Define the build targets in terms of the traditional DEBUG/REPRO/etc labels
+# Compiler flags
 SYMMETRIC_FCFLAGS := FCFLAGS="$(FCFLAGS_DEBUG) $(FCFLAGS_INIT) $(FCFLAGS_DEPS)"
 ASYMMETRIC_FCFLAGS := FCFLAGS="$(FCFLAGS_DEBUG) $(FCFLAGS_INIT) $(FCFLAGS_DEPS)"
 REPRO_FCFLAGS := FCFLAGS="$(FCFLAGS_REPRO) $(FCFLAGS_DEPS)"
@@ -239,10 +237,10 @@ OPENMP_FCFLAGS := FCFLAGS="$(FCFLAGS_DEBUG) $(FCFLAGS_INIT) $(FCFLAGS_DEPS)"
 TARGET_FCFLAGS := FCFLAGS="$(FCFLAGS_DEBUG) $(FCFLAGS_INIT) $(FCFLAGS_DEPS)"
 COV_FCFLAGS := FCFLAGS="$(FCFLAGS_COVERAGE) $(FCFLAGS_DEPS)"
 
+# Linker flags
 MOM_LDFLAGS := LDFLAGS="$(LDFLAGS_DEPS) $(LDFLAGS_USER)"
 COV_LDFLAGS := LDFLAGS="$(LDFLAGS_COVERAGE) $(LDFLAGS_DEPS) $(LDFLAGS_USER)"
 
-
 # Environment variable configuration
 MOM_ENV := $(PATH_FMS)
 $(BUILD)/symmetric/Makefile: MOM_ENV += $(SYMMETRIC_FCFLAGS) $(MOM_LDFLAGS)
@@ -271,12 +269,16 @@ $(BUILD)/timing/Makefile: MOM_ACFLAGS += --with-driver=timing_tests
 .NOTPARALLEL:$(foreach e,$(UNIT_EXECS),$(BUILD)/unit/$(e))
 $(BUILD)/unit/test_%: $(BUILD)/unit/Makefile FORCE
 	cd $(@D) && $(TIME) $(MAKE) $(@F)
-$(BUILD)/unit/Makefile: $(foreach e,$(UNIT_EXECS),../config_src/drivers/unit_tests/$(e).F90)
+
+$(BUILD)/unit/Makefile: \
+  $(foreach e,$(UNIT_EXECS),../config_src/drivers/unit_tests/$(e).F90)
 
 .NOTPARALLEL:$(foreach e,$(TIMING_EXECS),$(BUILD)/timing/$(e))
 $(BUILD)/timing/time_%: $(BUILD)/timing/Makefile FORCE
 	cd $(@D) && $(TIME) $(MAKE) $(@F)
-$(BUILD)/timing/Makefile: $(foreach e,$(TIMING_EXECS),../config_src/drivers/timing_tests/$(e).F90)
+
+$(BUILD)/timing/Makefile: \
+  $(foreach e,$(TIMING_EXECS),../config_src/drivers/timing_tests/$(e).F90)
 
 $(BUILD)/%/MOM6: $(BUILD)/%/Makefile FORCE
 	cd $(@D) && $(TIME) $(MAKE) $(@F)
@@ -294,7 +296,7 @@ $(BUILD)/opt_target/MOM6: $(BUILD)/opt_target FORCE | $(TARGET_CODEBASE)
 $(BUILD)/opt_target: | $(TARGET_CODEBASE)
 	ln -s $(abspath $(TARGET_CODEBASE))/.testing/build/opt $@
 
-FORCE:
+.PHONY: FORCE
 
 
 ## Use autoconf to construct the Makefile for each target
@@ -330,10 +332,12 @@ ALL_EXECS = symmetric asymmetric repro openmp opt opt_target coupled nuopc \
 $(foreach b,$(ALL_EXECS),$(BUILD)/$(b)/):
 	mkdir -p $@
 
+ifdef DO_REGRESSION_TESTS
 # Fetch the regression target codebase
 $(TARGET_CODEBASE):
 	git clone --recursive $(MOM_TARGET_URL) $@
 	cd $@ && git checkout --recurse-submodules $(MOM_TARGET_BRANCH)
+endif
 
 
 ## FMS
@@ -362,6 +366,7 @@ $(DEPS)/m4: ../ac/deps/m4 | $(DEPS)
 $(DEPS):
 	mkdir -p $(DEPS)
 
+
 #---
 # Verify that the coupled model drivers can be compiled.  This does not verify
 # that they can be run, since it would require external submodels.
@@ -608,7 +613,6 @@ $(eval $(call STAT_RULE,dim.h,symmetric,,H_RESCALE_POWER=11,,1))
 $(eval $(call STAT_RULE,dim.z,symmetric,,Z_RESCALE_POWER=11,,1))
 $(eval $(call STAT_RULE,dim.q,symmetric,,Q_RESCALE_POWER=11,,1))
 $(eval $(call STAT_RULE,dim.r,symmetric,,R_RESCALE_POWER=11,,1))
-
 $(eval $(call STAT_RULE,cov,cov,true,,,1))
 
 # Generate the half-period input namelist as follows:
@@ -667,33 +671,50 @@ test.summary:
 run.cov.unit: $(foreach t,$(UNIT_EXECS),$(BUILD)/unit/$(t).F90.gcov)
 
 .PHONY: build.unit
+.NOTPARALLEL: build.unit
 build.unit: $(foreach f, $(UNIT_EXECS), $(BUILD)/unit/$(f))
+
 .PHONY: run.unit
 run.unit: $(foreach f, $(UNIT_EXECS), work/unit/$(f).out)
+
 .PHONY: build.timing
+.NOTPARALLEL: build.timing
 build.timing: $(foreach f, $(TIMING_EXECS), $(BUILD)/timing/$(f))
+
 .PHONY: run.timing
 run.timing: $(foreach f, $(TIMING_EXECS), work/timing/$(f).out)
+
 .PHONY: show.timing
 show.timing: $(foreach f, $(TIMING_EXECS), work/timing/$(f).show)
+
 $(WORK)/timing/%.show:
 	./tools/disp_timing.py $(@:.show=.out)
 
 
-# Invoke the above unit/timing rules for a "target" code
-# Invoke with appropriate macros defines, i.e.
-#   make build.timing_target MOM_TARGET_URL=... MOM_TARGET_BRANCH=... TARGET_CODEBASE=$(BUILD)/target_codebase
-#   make run.timing_target TARGET_CODEBASE=$(BUILD)/target_codebase
+# Invoke the above unit/timing rules for a "target" code, e.g.
+#   make \
+#     MOM_TARGET_URL=... \
+#     MOM_TARGET_BRANCH=... \
+#     TARGET_CODEBASE=$(BUILD)/target_codebase \
+#     build.timing_target
+#   make TARGET_CODEBASE=$(BUILD)/target_codebase run.timing_target
 
-TIMING_TARGET_EXECS ?= $(basename $(notdir $(wildcard $(TARGET_CODEBASE)/config_src/drivers/timing_tests/*.F90) ) )
+TIMING_TARGET_EXECS ?= \
+  $(basename $(notdir $(wildcard $(TARGET_CODEBASE)/config_src/drivers/timing_tests/*.F90)))
 
 .PHONY: build.timing_target
-build.timing_target: $(foreach f, $(TIMING_TARGET_EXECS), $(TARGET_CODEBASE)/.testing/$(BUILD)/timing/$(f))
+build.timing_target: \
+  $(foreach f, $(TIMING_TARGET_EXECS), $(TARGET_CODEBASE)/.testing/$(BUILD)/timing/$(f))
+
 .PHONY: run.timing_target
-run.timing_target: $(foreach f, $(TIMING_TARGET_EXECS), $(TARGET_CODEBASE)/.testing/work/timing/$(f).out)
+run.timing_target: \
+  $(foreach f, $(TIMING_TARGET_EXECS), $(TARGET_CODEBASE)/.testing/work/timing/$(f).out)
+
 .PHONY: compare.timing
-compare.timing: $(foreach f, $(filter $(TIMING_EXECS),$(TIMING_TARGET_EXECS)), work/timing/$(f).compare)
-$(WORK)/timing/%.compare: $(TARGET_CODEBASE)
+compare.timing: \
+  $(foreach f, $(filter $(TIMING_EXECS),$(TIMING_TARGET_EXECS)), work/timing/$(f).compare)
+$(WORK)/timing/%.compare: \
+  $(TARGET_CODEBASE)
 	./tools/disp_timing.py -r $(TARGET_CODEBASE)/.testing/$(@:.compare=.out) $(@:.compare=.out)
 $(TARGET_CODEBASE)/.testing/%: | $(TARGET_CODEBASE)
 	cd $(TARGET_CODEBASE)/.testing && make $*