Well... I waited a while to get my NPC... but here are how things have gone so far:
Day1 - Shortly after receiving my Signal Pearl, I head out to Rolanberry as 42THF/NIN. My mithra NPC, Tsuim, and I start killing random EP-- gobs and such in Rolanberry, along with the occasional quadav. Occasionally we rest, then get back to fighting. I manage to get aggro from a gob... so I start fighting, and my NPC vokes. It wasn't long, but it was long enough to catch an uber StoneII to the face. I regain hate, but a gobbiebomb finishes my NPC. So I killed the gob and a few more out of vengeance, and head back to jeuno. Later I checked my Rendezvous Point and saw that she still had Scale Mail... but the legs we no longer scale mail, and had downgraded to what looked like the lvl 1 RSE legs (quite attractive, nonetheless).
Day2 - Determined not to allow the same thing to happen, I head out to Rolanberry as THF42/WHM13. We'd fight, then heal, then fight, and so on. Overall we did pretty good against the EP- and EP-- quadavs and goblins we were fighting, along with the occasional goobbue. I get a pt invite, so I wave farewell to her and talk to her to let her leave before zoning to Lower Jeuno (kinda lame, but I thought it was fun). Checking up with her again, she was now wearing Lizard armor... with those classy white suspected RSE bottoms still.
Day3 - This time I'm THF/NIN, and still in Rolanberry. I frequently check her health, making sure she doesn't get too low. It was rather boring... we mainly just ran around killing more EPs. Then she left. Nothing exciting this time. After checking up with her again, she was still level 30, but now had the options of changing her fighting style. I chose Attacker for the next time out. She was also wearing Chainmail, with those same white bottoms.
Day4 - Last night. I ran out into Rolanberry as THF44/NIN22, and we quickly began mowing through things. As attacker, I noticed she didn't voke, and instead just attacked constantly. She also seemed to use weaponskills a lot more liberally, usually Flat blade or Burning blade. I'd hold my tp... usually I'd be at around 150% when she used her WS. I'd SC it with Cyclone. One particularly awesome moment was when she used Burning blade, and I followed up with a Cyclone for a 40-damage Fusion on a Quadav. This time, I mainly fought TW's and was farming crawlers. We didn't stop to heal at all, which could explain the rather short amount of time she stayed with me, supposing the Stamina thing plays a roll. After checking on her, She's now wearing what looks like Scale Mail or Steam Scale mail, and no longer has those white bottoms. I also set her for Healing.