Don't forget to pre-HoT yourself, too. Regrowth/rejuv before a pull helps quite a lot to pick up initial threat.

Since you have a main tank you could probably even go ret on one of your paladins. The main reason to have two healers in the group is to keep up with the damage split between your warriors. If most of the damage is going to be on your druid in dungeons there's no real reason to have two healers. Could just build a traditional dungeon group with tank, 3 DPS and a healer.