Me and my wife duo it as BLM/NIN and SMN/NIN. Go in ES+Sleep the Dragon... she solo's the eye with Carby and then uses Astral Flow with Shiva on the Dragon and I help finish it off as well.

The normal strat would be to take some melees, a WHM and a BLM. Have the BLM ES+Sleep the Dragon and everyone else take out the eye quickly. When you are done with the eye just hammer away at the dragon. I would suggest that mages stand directly in the middle of the dragon. While they may get hit with AoE, it's better than getting drawn in and having their casting interupted.