I am of the belief that Pac has to be able to hurt you to beat you. If he can't actually hurt you then he may have issues making adjustments to stay out of trouble. Clottey and Mosley are the two welters I think he wouldn't be able to hurt.
Pacman......Clottey's problem has been his inconsistent activity rate and it would be real difficult to give rounds to Clottey when Pacman is always active and always moving. I would see a Mayweather like win from Pacquiao based on movement and activity.
tough one...i do believe that if clottey turned it up like we know he could...it could be a long night for pac...but i don't think anyone would be ko'ed...