Silva only has 4 inches on GSP.
As far as strength goes GSP said he would only take the fight if he had plenty of time to train and put on more muscle.
So that means GSP would be even stronger then he is now with near perfect technique in the takedown.
You are a self admitted hater Atom so the only real way to solve the riddle is to have them fight.
I'll pre-sig bet that fight too. I take GSP.