20kg is a big difference, if this is an exhibition fight, then Mayweather better watch out for some heavy punches because that could spell a knockdown or worse a knockout.
If they are both in the same level of skills in terms of boxing for sure it will be tough for Mayweather having his opponent that much of advantage. Though experienced wise He just simply need to avoid those punch and throw some good one from him.
The height is also an advantage because that means that Logan will have more reach than Floyd and that means it will be a fight where Floyd will need to dodge a lot of punches,.
In anyhow that reach advantage may help a lot as it can throw punches away where he's opponent still away from him.
The only advantage I can think of is the stamina of the fighters, the one who gets breathe more air than the other will definitely be the winner, the problem left there is the other might find that opportunity to clinch.
Good point. Stamina and the strategy, that's where Mayweather have a greater advanatge he won't be a non defeated champ for nothing.