I am having a hard time with this one
on one hand
Pacquaio is p4p #1, and he did weigh in at 148 for a lightweight fight which tells me, he is probably in the Mayweather size category
But on the other hand
He isn't a defensive genius like Mayweather, and the size factor plays a bigger role because of that fact.

Like I said at the begining for Pacquaio to put on 13 pounds for his lightweight fight, he must walk around at about 160, which means he should be fine to fight at 148. I mean Henry Armstrong beat an old legend at 147 when he was still fighting at featherweight. I am not trying to compare Pacquaio to the second best fighter in the history of the sport, but there are a lot of similarities between the two, scintillating work rates, and speed, fearless, Pacquaio has more power, but Henry threw more punches.