If by setup you mean skills, stats and gear, mine would go something like this.
Anatomy
Healing
Fenceing
Tactics
Magery
Resisting Spells
Poisoning
100/95/30
For gear I tend to use mainly chain armor, plate arms and gorget, and bone gloves and helm.
About 30 of each reg, about 12 or so of each pot and a vanq/power warfork for poisoning and a vanq/power spear or short spear for para blows.
I know a lot of people would suggest giving him more intelligence so I had more mana, but I'd rather keep my dex around 85 with all my armor on so I kept a 11 second bandage timer.
I don't really see many dexxers around here with poisoning, I mainly see axxers. But Poisoning's a really good skill to have on a dexxer if you're willing to carry a few dp pots on you. A lot of dexxer's and mages I fight on the field fight me until my poison hits them, then they call me a *** and run