That looks/feels a lot like the Cerilica Truism approach (arbitrary mixing).

Will have to keep it in mind for when I get a printer which does nozzle/toolhead switching.

You can use it with any printer if you're willing to swap the filaments manually.

The print file will have pauses inserted at the layer swaps. You manually swap the filaments when it pauses. There are only a few layers and colors so it's not too hard.

I have a printer with four filament changer --- my predilection for this is mostly a concern for waste --- plus, I want a 4th 3D printer....