So I went back to the original three quarts of paint I had purchased for the bathroom, but instead of using them full strength, I mixed each one with white in a 1 part color, 2 parts white ratio.
To achieve that look, I just painted the first color up to the corner, and then started at that corner with the next color, making sure that they didn’t touch so that the colors wouldn’t get mixed.
That center painted rectangle bothered me, so on the spirals that had already been painted, I added three strips of tape and painted the center part white.
On the ones that hadn’t been painted yet, I added more tape to the design so to eliminate the center painted rectangle.