Rainbow keyboard - distribute colour spectrum across all keys

[Bachaddict]

Don't see anyone else mentioning this so creating this issue.
I want to have an even rainbow, ideally 1-2 cycles across the whole keyboard, but across each octave would be acceptable too.
Trying to set it up with the given settings looked quite tricky unless I can find a tool to come up with the hex codes for each key.

I only know python but I'm happy to do what work I can to make this happen, e.g. scripting some RGB tools if a CPP programmer can help translate them