No one on neither my mom or dad's side every broke 5'8 and I'm 5'6. I have a medium bone structure so off the top of my head I'd say around 160 or so in contest shape maybe 170.
I'm a big believer in a size advatage but zyzz is by far large enough considering the extreme difference in mobilty and speed favoring zyzz. I say zyzz beats the shit out of jay culter very easliy. I dont think it would even be that much of a fight.