ToC and Offensive DispellingFollow

Unlike pvp where the hit cap is lower, these mobs behave in the same way as bosses meaning you'll need quite a lot of hit to cap. Its not really worth chasing really. I always find disc is great for this because I can spam massdispell quickly and cheaply to get rid of bloodlust for example.

It's actually quite worth it to put on some hit gear for this encounter. I've got a hit staff, robe and trinket which when combined with my normal healing gear put me at +11% hit; 18% I think is what needed to never miss. All I lose is a bunch of mana regeneration and a tiny bit of crit. Seeing as I leave that fight with 60% mana even on 25-man and I can get up to 60 dispells in the first 2 minutes of the fight, I'd gladly drop the mana regen.

That said, I was in the somewhat lucky position to get some +hit gear for my 'holy DPS set'. If your guild is cloth heavy or hasn't been farming Ulduar for too long you won't have any hit gear and obtaining some will be a pain.

To be honest, I usually just dispel through them =P. They mean a 5 second silence where I'd otherwise be standing around doing nothing; disc is horrible for raid healing throughput and random people either get 1-shot or are at 100% - I leave the pallies to deal with that.