Floyd was in his prime when he fought Ray Leonard in the late 70`s with an injured hand, by the time he lost to Starling in the mid 80`s he had faded, in between that time what if Roger could have moved up to 147 and met him (if in an alternate world they weren`t brothers) who was better in their primes P4P also?
Roger didn't fight at 147 until around 1994 In the late 80s he was prime but would have to pack on about 5-7 lbs. Floyd was past it by then so I'll go with Roger.
Roger was at 130 to 135 at that time. He couldn't fight at 147 then. Pound for pound, Roger was clearly better.