Turning off auto-save and quitting and doing the drill over is pointless and takes forever. Just do the dribble drill or the steal drill. If you get it, great. If you don't, just move on. You can then sim through the single point experience games (when you look at the calendar before each game, if the game isn't highlighted in gold, you don't get double points), or sim until you get another drill if you want (you get a drill every 5 games I believe). Then just spend those experience points on something else and focus on earning speed in drills. It's much more cost effective.
If you just keep going for all speed and quiting and replaying drills, you will end up with a super fast crappy guy, and you will have wasted tons of time you could have spent improving your player in the meantime.