Changing weapon skills can be used to change what weapon the NPC uses by default. This doesn’t appear to work correctly for armor – the NPC will only wear armor based on the skills set in the TES CS. If you know the item ID, and have either Tribunal or Bloodmoon, you can use the Equip function to force the NPC to use it (forum Info/Vorwoda_the_Black). See the tips and tricks section for an example.
What's not obvious is the range of acceptable values for a skill: its not just 0-100 as you might expect. In fact skills appear to be stored as a float so you can set some large numbers in there, but there are some checks: you can't set negative values, and decimal points are discarded when saving/loading (Thanks FreshFish).
