There does not seem to be any master schematic to the modules floating around. If you read around here on the forum you will see that alot of module have different values from module to module. Hope that makes sense.
So the "stock" answer you may get is something along the lines of " you should read up on amps and learn how the circuit works". Also, you should be able to trace the board on your own before you start tinckering with modding a module.
Me and a buddy of mine modded some of his modules and it was a fun and interesting experience. He had some know how about modding amps, so I got to learn alot. The interesting thing about this was that haveing a master schematic would not have helped us very much. What we did was experiment with different values based on our style of play and tones we were trying to achieve.
I hope this was a little helper.