I think Jack Britton is a much greater (résumé and Achievements) fighter but I think Mayweather wins here. His defence would help massively and I could see this as a boxing lesson
What's the pro-Britt argument? (honest question, I don't know much about him) Does it basically boil down to "he beat more ATGs than Mayweather so he probably beats Mayweather"?
I posted some stuff on him here https://www.boxingforum24.com/threads/where-does-jimmy-britt-rank.623407/ I added some of that to wikipedia.
I've read that Britt's cleverness forced Gans to outbrawl him. He looks pretty good against Nelson too. This content is protected Still though, Mayweather is a tall order. If Gans could adapt and outlsug Britt, Floyd probably can as well.