i'm not sure but I will admit I have been able to take really big cocks in my younger years...(one I was in the emergency room because of my determination to fuck him back hard)
but you can be rest assured that if I was paid to fuck him....i would give it my all and if my all was only 1/2 - 3/4 of the way in..I would stop cut my losses as I would not be turning in a good scene or at least appolize to the fans for not being the whore I was paid to be.