Yeah, but it's still the skin we're talking about in this battle. When I say how much of it is Hulk, I mean his strength level and power. The One Below All picked him for a reason, after all.
That is, how much of it is Hulk's skin's power (if you so choose to put it that way) vs. how much of it was power built up/pumped up by TOBA *into* Hulk's skin.