Quote Originally Posted by Wurfelrolle View Post
The new FAQ/Errata addresses this; the basic official line is that your base should have at least one more model than the unit one size smaller (i.e., if a regiment is 20 models, then your horde base should have at least 21 models on it). Unit dioramas are a seriously cool aspect of the game.
It's worth noting that's the absolute minimum though. The base should still look like a valid unit. Just taking half the guys +1 and placing them on a bare moving tray is technically allowed but not in the spirit of ensuring the battles are a visual spectacle.