Poppycock. Your cube will be fine if you do that. Besides, no one said you had to have equal gold numbers for each guild if you put the Finks there. Really, no one is going to notice (during draft) if you run 60 blue, 60 black, and 3 Dimir cards, but 60 white, 59 green, 3 Selesnya, and 1 Kitchen...