I think that AttacKat's post may be correct. My previous experiment bounced me back to Millcorn yellow. SO I've done one more experiment to see if I can get a more yellowy yellow than Honey (OK, let's be honest, I want the word 'Gold'. :-P) so from millcorn I played with rotating through Pears, Apples, and Pineapples (Green up, Red up, Blue down), and I found it REALLY interesting that I started getting a color change proc after each fruit, so I don't know what I'm dancing between there. finished that off with a Pineapple, so I'll probably wind up back at Honey. FFFF00 is as yellow as you can get, and that set of fruit should get the choco as close to that as the game allows.