I built a cube for my commander group, originally there was 30 Legendaries for each color, 20 for two colors, 10 for tri, and as many of the quad and five colors.

How to play, Legendary Creatures and Planeswalkers can be commanders, and treat all two or less color commanders as though they have partner.
20 card packs - 2 picks at a time per pack.
Singleton cube no repeats.

Card draw and mana fixing are key.