Definitely throw this one in the main forum -- I'm morbidly curious how others will answer it.
The starts, if I'm not mistaken, will impact how quickly the player picks up work ethic (the type of student the player is "in the classroom and on the court" also impacts this if you have that data from scouting trips in recruiting). The attribute gains themselves though, I believe, are a function of minutes played, potential, practice patterns, HS GPA and WE. So I would say the WE of a kid getting to start but 5 mpg would grow faster than if he was coming off the bench, but the kid that sees 15-20 mph will gain more over the course of a season because the WE gain of the first kid won't come close to compensating for the minutes of playing time the second kid is seeing.