So are you using all 5 of yours at one time? Do you complete this quest the first time you are doing it?

Sounds like you found a little multiboxing gem of a quest item. I'd say hurry up and grind the crap out of this b/c odds are it will get nerfed at some point. Also sounds like a pally will be better for this type of thing as quickly tagging a bunch of mobs is kind of hard for shaman.