How many snaps does Shep need...

Depends on the opposition.

Florida and Alabama = 15-20.
Arkansas, MSU, Ole Miss, Vandy, Georgia, Auburn=10
Washington, Tulane, ULL, Louisiana Tech=3

about the same number as Corch Urban Meyer gave Percy Harvey...

Imo, it all depends on whether and how much he can demonstrate the ability to realiably handle passing situations. We all saw how RP handled the ball when he started getting opportunities to pass, and yet he still almost never got to throw the ball until his 3rd year as a RS Sophomore. If they wouldn't even let RP throw the ball any meaningful amount as a RS Freshman, it seems it would take an incredible performance in practice and in camp for the staff to let Shepard throw it much as a true freshman. And I really believe that to be a true game changer there has to be the threat of him passing the ball. If all he's going to do is run it, then he really isn't going to be much more of a threat than Keiland or Scott or Murphy or any of our other playmakers. But if they do let him become a legit threat throwing the ball (and he can handle it at the SEC level), then he could be a true game changer with just 5 or 6 touches (maybe 8-10 snaps) per game.

The question mark in my mind is Crowton. Jimbo was the OC when Perrilloux was a FR and a RS FR, so maybe it was his call and not Miles' to keep him away from almost all passing situations. Crowton may be more willing to take the chance with a true freshman, if it is up to the OC and not Miles.