Floyd was plain and simple much better than his Uncle. Roger was certainly a bigger puncher, but that's his only advantage. Floyd late stoppage.
This is not an easy fight by any means and I hate to tell you but Roger could box with the best of them and had a cannon for a right-hand. The best chance for Floyd honestly would to be and try and catch Roger like Chavez did but if he walks into that righthand.........
Oh I promise you Roger would have connected. He was lighting fast as well and if he can find PERNELL WHITAKER's chin he would find Floyds.
I don't see an easy fight here. Roger Mayweather was wicked boxer/puncher. At his best he could be (Hearnslike) long left jab, sharp right cross. With Floyd being a boxer as well Roger would have the room he needs to get his combinations off. Floyd may apply pressure eventually if that is an adjustment he wants to make. Floyd could punch at 130. He was an awesome force at this weight. He had it all. He would just be durable than Roger even after getting hit more than he was used to. Floyd by KO
I think Floyd hit harder at this weight then when he moved up but at NO TIME could he come close to hitting like his Uncle.