You 're on a good path.
-Darker "Red" spots on the $1 would provide nicer contrast, without merging with the frac.
-On the $5, NOT chocolate again please, even if you 're in love with it. It's going to be used (inevitably as it seems) on the $500 and they 're supposed to play together in a $5/$10 game. Try Imperial Blue and Orange spots on the DG Light Yellow.
-Try "Pink" (not DG Pink) on the $1,000
It seems nobody could shift you further than that
About the molds: Very much theme-dependent, but the best-sounding ones are those with two concentric circles on their perimeter.