I thought i read somewhere that size isnt permanent amd u can change the same character's size between matches.
Sorry, you know, I think I might be wrong. Disregard that. Huh. I thought you couldn't but according to some older info you can. That may or may not be accurate, I don't know, I just don't know anymore!
It sounds like you can actually change between matches though. Adds less diversity per character, but probably better as a whole, considering you now don't have to restart as a new character after unlocking a bodytype for the first time.