Lately, I have been investing a lot of time working on my zon's merc. Specifically, trying to get him to lvl 96 from lvl 95. He is an act 2 defensive aura merc and comes in quite handy. Anyway, aside from lvling him I want to get the best gear I can for him w/o wandering into the very exotic stuff like extreme rune word combinations which I cannot afford. His current gear is this:

Veil of Steel helm

Gladiator Bane armor

Eth Bonehew axe

Considering armor choices what would be a better match? Steel carapace or Duress? Any ideas?