I think the more important question is whether PBF be able to hit Hatton so he would headbut the turnbuckle like he did in the last fight ?
Mayweather wins everytime, there is nothing in Hatton's arsenal to suggest he had the beating of Floyd in any department.
Hatton would give Mayweather a much better fight at 140 than at 147, whether he would win or not is debatable. The best opportunity would have been in 2005 - when Mayweather was struggling to make weight, rather than in 2007 with Floyd established at 147. Our American friends take the **** out of Hatton because of his lifestyle out of training (rightly so lol) but the fact remains that 140 has never been a struggle - generally a shift up in weight is made when making weight is too much trouble, or in Hatton's case, because that's where the big fights (and bucks) are.
Mayweather has never remotely struggled to make weight in any division. Out of training he is under 150lbs; in the age of fighters regularly dehydrating 15lbs the day of the weigh in, Mayweather could still easily be fighting at, for example, 135lbs.