You know, there is an official book that lists them.
Lesse:
Yamamoto mobility: 100
Soi Fong mobility: 100
Aizen mobility: 90
Byakuya mobility: 90
Shunsui mobility: 90
Histugaya mobility: 90
Ichimaru Gin mobility: 80
Tousen mobility: 80
Ukitake mobility: 70
Unohana mobility: 70
Zaraki mobility: 60
Komamura mobility: 40
Mayuri mobility: 40
Most of these make sense, though Hitsugaya strikes me as a little high. Perhaps he has that speed, but just doesn't have the skill at high-speed techniques that Byakuya does (not everyone at the same level has exactly the same speed). Ukitake's probably just as low as he is because of his sickness.
Yoruichi, Urahara, and so on have no stats, just the original Gotei 13 captains.
The stats reference each Captain's SPECIFIC POTENIAL, and therefore are not comparable to other captains. If anything maybe one could compare there individual growth in each catergory..like speed for instance, those whose stats would be at 100 would be presumed to have FULLY Mastered their abilities in that catergory!
However....
Clearly there are differences between the MAXIMUM POTENTIAL of each Captain! Which is why it becomes difficult to actually compare the stats.
Say for instance that.. from the above you have Byakuya at 90, and Zaraki at 60 where as you have Soi fon at 100, her stat of 100 denotes that she has reached the pinnacle of her ability in that stat! Which may or may not be superior to that of a character like Byukuya whose shown at 90, due to the fact that he still has 10 potenial 'pts' of ability to gain.
Same with Zaraki... he's at 60, most likely due to the fact that he doesn't spend much of his time or effort attempting to enchance these abilities, which leaves a lot of potential for growth in this catergory as well as others.
In Conclusion:
Due to the individual personalities and talents of each Captain they may or may not attain full mastery of each Catergory....and even if they did somehow all attain 100s across the board, that WOULD NOT make them all comparativally equal to one another in terms of 'power' output, only in title..as in you could call them all "Grand Masters" or something!
ONLY IN TITLE