Noting about Spinks' fights wtih Mayorga or Karmazin mean anything about his fight with Mayweather because IMO he can't deal with a puncher with pressure all that well. However Mayweather hit with more substantial punches against Zab in the first 4 rounds though he landed more, and one reason IMO is because he was comming forward trying to pressure Zab, but also Zab was able to get out of the way of Mayweather's lead right hand which really doesn't work all that well from a distance against a guy almost as fast as Mayweather. ANother thing is that Zab couldn't catch SPinks with 1-2 until 6 or 7 rounds into the fight, and that even in the second fight Spinks was still up on points when he lost, but there are other factors like Zab isn't very good against quick southpaws like in his fight against Demarcus Corley, and that SPinks just had his number while PBF is much better against a variety of opponents so for me it is an interesting match up.