I made this separator as a solution for coils where some plastic remained. It is suitable for internal diameters from 8 to 11 cm (approximately) and is printed very simply and quickly.
My tests showed a satisfactory result. I used one divider for two colors, but I believe that you can place three colors, for this you need to make a second divider. The most important thing is to gently wind the thread without overlaps. I did not test on a coil located horizontally, I am afraid that there part may cling to the thread, be careful.

BQ Hephestos 2

No

0.3

40

There are several prototypes in the photo that I made in search of a solution.