I think this is rather an enlightening approach.  We may learn something new along the way.  BTW, I see in your Color_Math node explanation you are using 2 primary  and 1 secondary colors.  Have you experimented with the addition and subtraction of secondaries to see what effects you get.  Also you stated:

*Quote: what "Green" is to Poser. It's 0, 1, 0. We know that? Right? This is an absolute. To Poser, when you say "Green", it thinks 0, 1, 0.

*Is that correct?  I think Poser should interpret that as 0,255,0.  The mathematical expression of a color in it's channel should range between 0 - 255, not an on-off switch integer.