For large woman speaks her weight. She is a little stronger, but quickly get tired. Slimmer woman is more agile, faster, more resistant to exhaustion. Smaller and slimmer woman can win this fight.
If it was a fight wrestling my money on a thick woman, but if it's a catfight, then the smaller woman can win. Even if at one site when fighting fat woman is on top, slim can drop it using the painful grip hair, boobs, or even a fingers in the eyes. In my argumentation going to the fact that if pain can be influenced on the opponent, then mass loses meaning.
I vote for the smaller and slimmer woman.