I setup for this fight right where you first enter the room. You'll know which area I'm talking about because it's the biggest open area in this room, which is exactly why I setup there.

I put the toons back against the wall for the "shield" part of the fight, reason being so that when the casters come out of the door you first enter this room from, you can LOS them on the wall bulkheads. Once we start on Novos himself, I move them out into the middle of that area. The reason I say all of this is that I think it's crucial to my handling of the fight.

Once they are positioned there and my tank is on him, I rotate the camera almost 180 degrees around, such that I can see Novos, my tank, and the shaman in the background. It helps me keep track of the blizzard. When blizzard casts, I just strafe the shaman left/right out of it immediately (you have keybinds to strafe the slaves, right? If not, get some). I find it much easier to try and keep of all this when they have plenty of room to move around, and aren't fighting around pillars and stuff like you have at the bottom of the stairs.

I'll try to get some SSs or something if I can remember next time I go through.

BTW, if adds do get to your shaman, remember thunderstorms.

P.S. It is definitely possible to heal through the blizzard, you just gotta spam a couple CHs. I still recommend just moving, makes your job a little easier imo.