I'm getting better with Skadi on heroic UP, still haven't defeated him in multibox (done him solo bunch of times) but getting him down fairly reliably now, just wipe when he is down to mistakes. What I've found it best is to just to hang out at the entrance farming harpoons (looting on my tank) until I have 6-7, then I reset the encounter (run out). I run back to the tiny room and huddle in there, hand my harpoons to one of my shamans, who then goes off and aggros the boss and runs back to the harpoons. Meanwhile my pally is tanking everything and I am dropping magma totems every cooldown. As soon as Skadi is in range I shoot him down and he lands. I can do up to this fairly reliably now.

After that it goes to hell, usually there are a few adds still up, one guy is outside by the launchers and everyone else inside. People start dying before I can really react quick enough. I know you are "supposed" to position your group a bit away from the tank and taunt midway when he starts whirlwinding, but I just can't react fast enough when my group is all split up between the room/launchers and theres really no place to run, while adds are still up. Gonna haveta think about it a bit, maybe start running the group out right before my guy shoots the last harpoon.

I found running the gauntlet normally just didn't work for me, my tank would get webbed constantly preventing me from running to harpoons quick enough (so damn annoying!!) and someone would pull aggro and die while my tank is rooted. Definitely one of the most unfun bosses I've found so far

Magma totem does work awesomely in the room, it pretty much kills everything, a few thunderstorms and CLs finish any remainders.