I'd put '93 Holyfield as the prime version myself...better experience, heavier punching, while still retaining the stamina and speed of his youth.
Holyfield beats any version of Tyson. Holyfield was mentally tough and Tyson was not. It does not matter what version of Tyson he faces he wins every damn time. Holyfield by (T)KO any version of Tyson
I see this a little bit differently, I suppose. Versus a prime Tyson, Holyfield's head first, lean forward, hands-up, forehead-in-your-chest style actually plays into Tyson's viciously fast left hook to the body, left uppercut combination. Granted, Holyfield has one of the greatest chins of the modern age, yet has been seen wobbled quite often and was taken out by Bowe. That having been said, I don't see Tyson with the mental toughness to be able to stand and trade with Holyfield the way that's required to give Tyson the decision, with Holyfield swarming, clutching, and throwing countless punches from inches away. Versus a prime Tyson, dudes like Tillis lasted the distance by staying away from his power - otherwise they all went down. If it goes the distance, Holy takes a close decision. If not, Tyson KOs him.
I agree, especially for facing Tyson, those extra 12lbs would help a lot. I do think it went at cost of his stamina somewhat, but he did seem to have increased his power a bit. Plus he was a smart fighter from there on, instead of slugging it out like he did in '91. He'd lose if he tried that with Tyson. But otherwise, i think he has Tyson's number and takes him by decision.
Holyfield wins everytime he fights Mike he's mentally stronger, better stamina, and he's more disciplined and focused..
We already saw how this ends. A shot-as-f*ck Holyfield outclassed a Tyson that was only slightly less than his best. Prime for prime, Holy beats him even easier.