As it turns, the explanation about her larger size being an issue weren't from the behind scenes videos or Kendal Cronkhite's Dreamworks Animation Masterclass. It's all in one paragraph from Page 34 of The Art of Madagascar Escape 2 Africa:
>Originally, Gloria was much more robust — a super-huge, round character. Besides downsizing her to fit with her personality traits, the filmmakers also ended up slimming her down significantly for technical reasons. Because she was so big, she would bump into everything, including herself, with every movement she made. This created a number of technical challenges, as collisions have always been difficult in CG. It also made for a very physically disruptive character who wasn't elegant or reassuring in the way that Gloria was meant to be.
I'm sure I typed this all up before but I wanted to keep all the sentences rather than in separate arrows. I also don't want to scan my copy.