I use both 16's and 15's, but at least till now...mostly 16's.
If anything, I seem to get the 8-10's more often with the 16's. Not sure what to make of that. Maybe I throw harder or get more revs and more of an entry angle with the 15 lb balls?
Anyway, I'm still a 16 lb guy, though lately I've had a leg injury (pushing off leg, not the one that takes the weight on delivery) and find that I'm a little tentative about throwing at full speed. That could be why I'm coming in a little light and getting more 8-10's. Ironically... Maybe I should at least temporarily (till I heal) use the 15's to generate a smidgen more speed on the delivery.
In fact... I Practiced today and threw 3 games and had zero 8-10's Yippee!!!
But was just practice and nothing much at stake. Will try to remember what I read here later in the week (in league) and even if I can't avoid the 8-10 altogether, knowing why I left it, should help me deal with it better.