My advice to you would be to not stop healing. It's one of those fights where you're bound to have some mana issues unless both healers are syncing up well. I'm a WHM with 5.1k mp and I still need ballad for a good portion of the fight. The reason for this is I find no time to be idle. It's one of those fights where your tank can be at max hp and drop really fast (especially when dreads are up). Next is always ss/ requiem for allagan field. also leech/esuna the tank. and don't be afraid to ask for ballad. that's about it for now.