I have yet to see a guide on capping spell crit, so here you guys go. I had to figure this out myself but I got it. I did this with rev 1506 ArcEmu. It can be done with almost any other lower revisions I'm sure as well.
Ok so if you follow this guide [Pic Tutorial] Modifying the Weaponskill, Block, Parry, Dodge and Crit Chance Caps - AC Web
to cap all your Parry/Block/Dodge and Melee and ranged Crits, here is how to additionally cap your Spell critical Value.
Go into your SVN ArcEmu folder and go into ArcEmu\trunk\src\arcemu-world.
Open up player.cpp with any word editor you'd like.
NOTE: Some people have a diff route, but just find player.cpp. It will most likely be in the designated location.
1. Click Ctrl+F and search for // Update spell crit values in fields (this is where we will work)
2. Replace SetFloatValue(PLAYER_SPELL_CRIT_PERCENTAGE1 + i, SpellCritChanceSchool[i]+spellcritperc); with
SetFloatValue(PLAYER_SPELL_CRIT_PERCENTAGE1 + i, SpellCritChanceSchool[i]+ min( spellcritperc, 70.0f ) );
3. Change the 70 in your new line to whatever you wish your spell critical cap to be.
This is pretty simplistic, and I did this with rev 1506, so previous revs player.cpp might be different. You would think that this looks easy, but you gotta be carefullhow you edit the file cause one misplaced Period will mess you up big time.
Thanks to Charlie9809S From AC-Web for getting me going on this.