Forrest was the kind of guy who would have one top fighter’s number and look limited against another; just look at the Shane and Quartey fights. I imagine he would’ve taken Oscar down to the wire because everyone ran close with Oscar, but gotten schooled by Floyd and likely broken down and stopped by Tito. I think he might’ve been able to beat the fading 147 version of Whitaker. Jose Luis Lopez would’ve been a very even matchup for him.
I know you don't like Hatton, but you're not being honest about this. Hatton was smaller than Mayweather, he was the Ring champion at Light Welterweight. Hatton was 5'7" compared to Mayweather's 5'8", and had a reach of just 65" compared to Mayweather's 72". It was obvious watching their fight that Hatton was the smaller man. He had just one previous fight against a noticeably larger man Collazo at Welterweight, and he struggled a bit in that one, although he knocked his opponent down in round one and won (despite what Max Kellerman said, he feels the same about Hatton as you do) . Then he returned his more natural weight and easily defended his titles against Urango and Castillo.
Look, you do this thing in your posts where you omit pertinent info as if I won’t notice. You can stop doing that. Boxing is a weightclass sport. Hatton fought his fights at 140 and 147 at a higher in ring weight than Floyd did at 147. Hatton was a little off for Collazo, but was in career best form for Mayeather. Mayweather fought at feather in the Olympics.