I favour Zidane, Steiner, Eiko and Garnet (will not call her Dagger) Sometimes I may exchange Garnet for Vivi but I like to have two white mages cos Necron is TOUGH

I make sure everyone has as full status protection as I can make it.
I put Zidane on High Tide and use his trance
I put Steiner on High tide and use his trance (I also make use of Climhazzard)
Eiko is useful for Curaga and Full Life but it is Holy that makes her super useful
Garnet I only use for back up Curaga

And if I use Vivi instead his -aga spells plus if I get Doomsday I can get Steiner to use Doomsday Sword.

Please let me know what the rest of you do....