Does catching it on the second or third groove mean you hit the golf ball a little thin and don’t take much of a divot?

Yes, just like when we do the tic-tac-toe drill. When the low point is four inches, we can still hit fat or thin shots. The thin shots will have a smaller divot, the fat ones a larger divot. For these wedges, we want the smaller divot that actually starts “after” the ball not at the ball, but the low point is the same. Standing taller at address is the most simple way to accomplish this.