Looking at eqemu source code in the various places (fairly well commented) will give insights. Depends how keen you are at scouring c++ source code (or even if you can).
Chances of success in various tradeskills are quite well understood here i believe so maybe check out the tradeskill area here.
https://wiki.project1999.com/Game_Mechanics offers some ideas of how shit works.
Others here may have better answers for you.