big swet has more swet, so more swet is needed

also may want to look at the actual coloring of swet balls

No

The main problem I see here is that giving different swet balls different colors will prevent them from stacking together even if done via nbt and color providers, which is not exactly a great thing unless each color has its own properties.

I created a system a while ago to allow different colours for items without preventing them from stacking, by simply allowing a stack to merge into a stack of a different colour - think terraria slime. I used it for parrot feathers and coloured shulker shells - but if I can find the source code again, it may be useful here

If you can find it, I think it'd be useful, and would make things look very nice.