Tyson Holyfield Spinks Witherspoon Norton Spinks and Witherspoon were in their prime, Norton wasn't. Spinks from the first Holmes fight was a better fighter than anyone Holmes fought during his entire reign.
If Michael got knocked out like Leon, Marvis, or Ocassio, then you could say he wasn't a heavyweight. But Spinks beat Holmes convincingly to win the heavyweight title. I can't put guys like Cooney/Weaver/Mercer above Spinks just because they were natural heavyweights. Spinks is top 5 for Holmes the same way Conn is top 5 for Louis and Foster is top 5 for Frazier (arguably).
It would take some incredible arguing to convince anyone Foster was top 5 for Frazier. I rate Foster enormously at 175 but he was a most ordinary heavyweight.
I only had Spinks winning the first fight by one point. I had him losing the second by four. So, I don't think Spinks won that 1st fight convincingly, no. He did look slightly better than Holmes in what was ultimately a big snooze fest where nobody really got hurt at any time.
You can also have Spinks winning the first by 4 points and losing the second by 1 etc. etc. It all depends on your scoring criteria. I think Spinks clearly won the first fight and lost the second one. But if you had to make a case for one fighter winning both fights, it'd be easier to back Spinks.
I can't make a case for Spinks winning that second fight at all. Holmes hurt him several times, and it was plain as day. Spinks never once hurt Holmes, period. In either fight. Spinks barely outslicked Holmes in the first fight, certainly a far stronger case can be made for Williams winning in the fight before (though imo Carl lost that fight...just barely). But that's just my opinion, asserted with respect.
I thought Spinks won 10 rounds. Larry was outjabbed and the only right hands he could land were to the body. Meanwhile he got hit by everything Mike Spinks threw. The only reason the scoring was close was because it was a DKP bout. Spinks was out of gas in like the 8th or 9th round and Holmes couldn't do anything about it.