I'm a typical house hack, but I'm friends with some truly amazing bowlers. I went up to watch one of them bowl a PBA regional, and he told he his philosophy on ball selection. He said he tends to use shinier equipment, sometimes even pearlized stuff, on the fresh with longer patterns, and he tends to use his more aggressive, surfacy stuff on the shorter patterns. It may sound strange, but it actually makes a lot of sense. If you're bowling on a 45-foot pattern, your ball is going to have very little lane left to make a move once it exits the pattern. As such, using something that holds onto its energy and can actually grab off the back is worthwhile. If you use a 500-grit duster, sure, the ball is going to dig in and read early, but it may have very little energy left when it comes off the pattern. Now, granted, he's a high speed, very high rev player who can do things with a ball most of us will never come close to. Still, the theory makes sense. I just mention this because you may want to keep that concept in your head when looking at ball selection. Going with something gritty might not be bad during practice in order to create some room to the outside, but once the lights go on, you may be better suited with something a little less aggressive than you would otherwise think.