About duelist..well i use
Str+4 Con-4
Well the reason is obvies i get like 1k p.atk(if there is like +20 enchant) and lose around 1k or 1.5k max(depends if there are custom armors that give hp or what kind of duals i use)

Wit+4 Int-4
This one is mainly for sonic move(i think works on barrier too not sure thought)..i need to cast it as fast as possible especially when i pvp with archer for an example.It gives and a bit better cd both on sonic move and sonic barrier(not 100% sure again..GoU works on force barrier but dunno if works on sonic barrier)
Most times i don't use another dye.U see +4 dex gives like 30 atk speed and 3 speed(i think can't rly recall for sure)and some critical rate that is useless for gladi(skills ciritical rate is not the same with normal critical rate...or so i think cause in most server gladi is fuc ked up ) and since from archer i get like 2k with -8 con i lose almost 2 crits and that's a lot cause in that time i can use storm+blaster in that time or try to get closer for baster+storm+tripple(or double cause i noticed in many servers tripple do same dmg with double or even LESS THAT BLASTER LOL? :P)

that's just my way ofc and can't be sure it's best(even thought it works fine )