This is a brand new cube! 360 card standard template 2 (50/50/50/50/50/50/60)Red, Blue, Green, White, Black, Colorless, Multicolored
I thought about that when writing!
I keep my color and guild sections even. For me, it's easy to keep the guilds equally represented and relatively balanced. However, the impact on draft and gameplay of going +1 or -1 card in a guild is marginal - even less so going +3 or -3 in a mono color. You could make a strong design / choice argument for doing or not doing this.
I do cheat with some cards, especially in mono-color. If I want to slot another land or colorless card in, I might see Phyrexian Metamorph in my colorless section and go "hm...you're a blue card now."