As long as we're wrapping this fun thread up, Andy, could you please tell us how you originally decided to divide the colors for the two Treehouse sets? Were you thinking "paint primaries" or "toy colors" VS. "the rest"; or was there some history behind it (Zendo box set or comparison of stock levels); or what?
The convention, established when the gameset was still strictly fiction (which was later adhered to by Zendo, among other releases) is for the basic colors to be Red, Yellow, Blue, and Green. When the Treehouse revolution came, it was a no-brainer to put RYBG in one set, the Xeno transparents in the other, and an opaque in each. The only question my new vision left unanswered was if the rainbow set should include the black or the white pieces.