Quote Originally Posted by Elthore
can unit sizes be changed during a campaign?
No, it is not save game compatible.

I remember when I first found this option (back in vanilla) I changed it to huge, loaded my game, and noticed nothing different. I remember thinking, "What did it make the unit models taller? I see nothing different." Then, like a month later when I started a new campaign, I thought I had broken something: I had like four times as many guys in each group.