My attempts at healing H HoR have gone best if I have one of the DPS set to cleanse duty. Just someone to lend an extra hand by getting the poison or curses off of people during the first part. Really, is more of a survival thing than a DPS race in the beginning anyway. If people who can CC do so, hunters MD to the tank, etc. it goes surprisingly well. *shrugs* We don't have a problem with this when my guild does it, but I can have a hard time convincing PuG DPS to do anything but lay down the hurt.
My bad runs usually involve a tank having problems with gathering mobs during the LoS pulls, or running somewhere unexpected while I have my camera dancing around thanks to the wall (since we're on that subject too...). A good tank makes all the difference in there IMO. I can't say I've ever had a tank get 1-shoted on me, so I could only speculate on what happened there (had the +50% magic damage curse on him? *shrugs*).
If the group decides to do a LoS pull, I'm concentrating heavily on tank heals and throwing down WG at every CD to help the DPS out. I'll remove the poison from the DPS if/when I have a spare GCD (the time when having a cleanse b!%(# helps ;-D), then I'll throw some RJ around if the tank damage isn't too high. I usually end up hitting Tranquility frequently during the first 10 waves.
In my experience, wipes happen when the tank misses adds and I get pummeled repeatedly. Meaning I'm healing me and not him, and that's no good... If I lose anyone it's usually the DPS, which isn't really the end of the world, since the first 2 bosses seem to be 3-manned fairly easily. Usually it's the DPS who are pulling aggro, or not breaking LoS with the casters anyway, so no loss. Really I just concentrate on keeping the tank up. The DPS? Well they're expendable for the most part. ;-)
During the gauntlet part I'm just staying near the tank and de-cursing immediately unless doing it means losing the tank (I guess nothing really amazing here, it seems easier then the first area... :S), and it usually comes down to whether or not the DPS can kill things quickly enough.
I don't know if any of that is helpful or not? I know I still have problems there too. Oh well, a 5-man that's a bit of a challenge is nice. :D
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That monster in the mirror, he just might be you. -Grover