Check out brunswickbowling.com and the drilling sheet provided for the current and older balls. They feature some good basic explanations for various bowler styles - just check out if you have a symmetrical or asymmetrical core, makes slight difference.
I also remember that lanemasters.com featured a nice PDF with basic drilling physics - but since they revamped the site, I am not sure if it is still there?
The rollrite.co.uk website has also good insights into ball physics.
With MoRich, I 'd be careful since their basic drilling suggestions are tailored to the heavy MB asymmetrical cores they use.
--------------------
DizzyFugu --- Reporting from Germany
Team "X": http://homepage.mac.com/timlinked/
"All that we see or seem, is but a dream within a dream..." - Edgar Allen Poe
