The best Ammo out of my Model 2 so far was a nice tight cloverleaf 5 shot group. Sadly it was old stuff I'd had since the early 90's........bugger. The point being try all the readily locally available stuff first. Otherwise like me you could find something that shoots fantastically, but you cannot readily get.
Another thing to bear in mind is that your performance will tail off on longer sessions so maybe limit it to trying 3 or 4 types per session.