Up to you, just make sure you don't take out too many that you become a target for melee characters. A necro can tank better than a zon because he can always have maxed dr and block. However, he needs more faster run/walk than a zon because he can't leech back, as a zon can, so he really can't get hit much.

/w *thesuck for duels.
I use only legit but will be happy to take anyone on 1v1 in a friendly duel =)