I use 5 healers. I have 2 melee and 3 resto. I pull with lightning bolts (about 2-3) and then just shock and melee, so I never need to interrupt anything to heal. I use 2 heals at once, you can do them alone, but if one gets stopped or slowed, you probably aren't very happy. I also like to spread out the healing done, so others can regen while not casting (5 second rule). I use owl and eagle gear mostly. It gives int for mana, spirit for regen and stam for staying power. Try food also, you should be able to use the 200 food. It gives stam and spirit, again to give breathing room.

/castsequence [target=focus-target-target] reset=12 Lesser Healing Wave, , , Lesser Healing Wave (alt 2/3)
/castsequence [target=focus-target-target] reset=12 , Lesser Healing Wave, , , , Lesser Healing Wave (alt 4/5)
/castsequence [target=target-target] reset=12 , , Lesser Healing Wave, , , , , , Lesser Healing Wave (main)

Hope that helps, good luck.

Oh, and PS, WTF on pushing ESC while you are typing a post, it erases it. CRAP.