Chun, you're saying that you want maxiimum backend snap. But that usually means the ball will be hard to control. So the key is to have the best of both worlds, which means you'll want slighty less than maximum backend.
Also, it depends on how much oil and where the oil is that you're bowling on. For more/longer oil, a shorter pin label stacked under the ring finger will do the trick. For more medium, a longer pin over the ring finger with the CG kicked out is probably best.
Pin axis is for drier lanes and won't hit well in carrydown. I would drill the XXXL stronger, because it's plastic. Pin axis will probably be overkill. =:^D
