I suspect that the common factor, will probably be that he smaller slower man had more power in most cases. In other words at least he had some advantage.
Surprised no one has mentioned Fitzsimmons Vs Corbett, though the weights for that one aren't known for sure I'm fairly sure it was more than 15Ibs, and I think there's a good chance it was more than 20Ib
I would probably lean towards saying Wlad hit harder than Liston, but Liston could take a punch much better.
Let's allow this. And also add Brewster-Wlad form page one, now allowed based upon the change to 15lbs.
Ah, I thought he meant Holmes-Ali? So, who thinks Spinks is slower than Holmes when they met the first time?
Easy win. Mercer vs Damiani Damiani was both bigger and had sharper punches. Mercer had that punch, though.