How much Wilder squats?

That's just simply not the way the biomechanics of punching power work. Arm length and leg strength? I'm surprised you didn't throw fist size and tricep muscles in there as important factors. You're way off base. Sorry.

 

Seems to me punching power mainly comes from the ability to transfer weight from one foot to the other at the right instant. "Step into it" as the old timers said. Of course there are pugilist who can accelerate greatly at the move giving them explosive power but explosive power is probably overrated. Evander Holyfield can flatten somebody just as well as Mike Tyson.