The main guy I am talking about is a real powerful guy with about 80 pounds on me. There are some guys even larger I spar with but he is the strongest. I have a bit more skill than him and better cardio. We have a lot of good sparring battles though, which usually involves me tapping him with armbars and triangles from guard and him tapping me with neck cranks and keylocks from sidemount.
I try to use mobility against him but really all he has to do from any bottom position is grab onto my gi and hug me tight. Once he's got me like this I can't move into another position or a submission(too strong), all he's got to do is flip me over and it's easy as pie for him.
Okay, word. When the dude has 80lbs on you, it's hard to stay anywhere but on the bottom. But for me, guys that are bigger by around 30-40 lbs, I prefer to play top.
Greg