If Lewis had to fight the best heavies of all-time 10 times how many of them would have at least been able to win 6 of those match-ups? I feel a prime M.Tyson would have won the most bouts out of 10 v Lewis.
Without overthinking things and including wear and tear, ring IQ, adjustments etc; here's mine: '88 Tyson would win six or seven, IMO. Ali is six or seven out of ten type deal IMO. Same with Holmes. I think guys like Sanders or Brewster could upset him ala Rahman/McCall, but it'd be a major upset. I think Lenny is on the same level as an early '90s Holyfield and '92 Bowe. Those two are 50/50 IMO, like Liston and Foreman. I didn't mention them as I'd pick Lewis in a one off, I wouldn't with the above. Taking into account the criteria I mentioned to begin with, then I'd pick Joe Louis to lose the first fight then KO him in the rematch, then obliterate him for every fight after that.