Re: How should Superman fight?
Personally I'd probably handle it like he's never had to fight in his life - unwieldly and inexperienced at first, but gradually getting the hang of it. It'd help to have an earlier scene of Clark or Superman at the Ace O'Clubs and have one of Bibbo's old fights playing on the tube, then later on when it comes down to the climactic bare-knuckles super-brawling, he makes like Bibbo with the entire city getting ringside seats. Y'know, the old "set it up/pay it off" bit.
"My folks came to the U.S. as immigrants, aliens, and became citizens. I was born in Boston, a citizen, went to Hollywood and became an alien."