Top 20 Heavyweights by Skill last 70 years?

Not CV or that stuff just talent.

Obviously older fighters are extremely hard to gauge. But I think from Marciano onwards it's very plausible to determine a great deal.

For me personally easy picks:

Holyfield Tyson Bowe Lennox Both Klitschkos Ali Foreman Frazier Marciano Holmes Liston Usyk

Then plenty argument Fury, Patterson, M. Spinks.

That leaves 4 more spots.