Is there a rule of thumb for what gems to put in Icebane crafted stuff? I know it will depend on how my stats stand otherwise, so I suppose I should ask what kind of stats am I looking for? I'm assuming that if I swap Icebane gear in for Saph and that drops me below 540 def that should be my first priority. After that, should I be aiming for a certain health milestone, or perhaps avoidance?
Gem to maintain 540 defense, and after that, put stamina on it. I've always tended to try to play to the strengths of any given piece, and the only strength of the icebane gear outside of FrR is stam. Keep 540 and stack the HP.
I don't use Frost Resist when tanking Sapph, I lose too much mitigation and threat stats, and tbh, it really isn't required of the tank to wear frost resist. I've found that the main cause of my death on that fight is due to not avoiding enough of his melee hits, and he hits fairly hard.
The resist gear is there mainly for the DPS and Healers, to help them resist some of the AOE damage, and we usually only go with one item per person, the chest piece, and do just fine. We have managed to get the achievement of <100 frost resist on both 25 man and 10 man, and although it is significantly harder on healing, its not impossible.
Icebane is top gear even on tank gear listings because of its 2-3 gem slots a piece. If your a BS you can tweak the gear even more with your additional 2 sockets and pop on a belt buckle.
I had no problems reach 540 defense, my dodge is ~19%, Parry/Block at ~16% each. My unbuffed health is 26500hp, if i'm up against a boss i'll pop my battle shouts, shield wall, last stand and rage and push 37k hp.
I'm also still wearing green gems.. as soon as i get more money i'll put on some parry and maybe more expertise/hit.
Not sure why anyone would think frost resist is geared toward anything.. its so easy to gem to match whatever you need it for.
Once you get your tier sets you will have a frost resist set you can carry with you as needed.