I use 1/4" bridge on everything and never had any problems. If installing grips, I use 3/8" lateral on middle finger and 1/2" on ring... if no grips, I use 3/8" for both. I would recommend trying to track down a copy of Bill Taylors "Fitting and Drilling a Bowling Ball." Its quite old, but in general its very informative... It explains in detail a lot of the pitch related questions.
S^2
--------------------
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"The Patriots strength got debacled."
-Emmitt Smith 2/4/08