Who's the greater LHW & why? I know there's no footage of Greb obviously but just in terms of resume .. I'd like to hear your thoughts.. here's an article with the stats comparing the two to get you started: https://thegruelingtruth.com/boxing/ezzard-charles-harry-greb-light-heavyweight-perspective/
It's Moore vs Greb that matters. If you believe Moore is very highly ranked and Charles has gone 3-0 against him, the argument is over. Imagine if Joe Louis went 3-0 against Muhammad Ali You have to roll Moore right down your list before you can have Greb above Charles, but if you do roll Moore down the list, you should have Greb above Charles. And that is the whole story for me.
One guy won a belt over Gene Tunney the other guy got knocked down a bunch of times by Bivins and Lloyd Marshall when he was in contention. I will go with the former though the former is more overrated the latter is more overrated at LHW.
Greb has the deepest and highest quality win resume in LHW history. Charles didn't lose at the weight once he got into his prime, avenging both his pre prime losses to the ATGs Bivins and Marshall, whereas Greb lost a few LHW bouts whilst prime. Both had series vs top 5 all time LHWs. Greb split his series with Tunney whereas Charles dominated Moore 3-0. I have Charles #1 and Greb #2, though if your ranking criteria is based solely on win resume depth in quality, then you should have Greb #1.