As a lefthanded bowler, on most shots you could get away with 3 balls, I think an Absolute would be great in oil, you can play straight up with it or hook it, a medium ball like a bruiser, smashR or nemesis and a plastic ball for spares. Those three balls pretty much can cover anything you see. When you start going for more equipment, drill up other balls for matchups only, like a medium ball that maybe rolls later when a ball that rolls sooner can't get the 7 out. Nothing wrong with having a few balls that react the same, just do it in different ways for carry.