You can also use ollydbg to limit mastery max level, character max level, also pet max level.
Use the search function for the "assembly guide on vSRO 188 and 193" topic.
And that one might be better.
For your skills, like Devil said, disable them server and client-sided.
Do a simple update statement, which logs onto the specific database and table, and uses the set service = 0 trigger on everything fitting this condition(s) "skill_ch AND level 81 and higher OR skill_eu AND level 81 and higher".
Yep, you have to write down that query on your own
Actually, there is everything on this forum, you just have to search for it, even for your monster hp and NPC with SuN stuff.