I was interested in trying to map out color wheels to the music (chromatic scale / wheel of fifths) so that I could see a visual representation of the relationships between various chords/scales, etc. however first I needed to determine a color wheel to work from.
I ended up spending a day or two making different 'base' color wheels instead; couldn't settle on one.
I was passively thinking about the circle of 5ths as I was working on these, and so noticed that it would just be a series of alternating split complements. Another thing I was interested in was the inversion of sharps and flats across the wheel of fiths, although upon consideration, the relevant aspect of that would really be the diatonic scale that would be produced, which I haven't gotten to yet.
Another hiccup I ran into is where to start. The audible spectrum 'loops' enough for us to hear the same notes at different octaves (so C seems arbitrary to me at the moment), but the visible spectrum doesn't; so I don't see any good organizing principle to abide by in order to choose which color goes with which note.