Unfortunatly the answer is, "it depends". Do you have any other NPCs (Magnus or Raven)? What is your build (tech/magic), and what do you use him for (a tank, pack mule, medic).
But for a basic over view of builds and the like check out
Terra Arcanum. It's a site dedicated to Troika games with lots of juicy Arcanum stuff - patches, guides, mods, you name it.
A quick glance at their forums and I found a
short thread for your perusal.