2 RNG or RNG + SMN
PLD
Something that can stun (PLD can sub DRK)
Healing.
That leaves one or two spots for whatever you want, those of which should be focusing on killing Spalls and/or backup healing. Although we did do a poll at the top of the tower with everyone awaiting to go in to see what the most useless jobs would be for the final BC, and the final results were 1.THF 2.DRG 3.DNC. We did end up taking 4 DRG individually through for the win that same night.
Edit: and by the way, WHM is great for this fight, especially if you have merits. PLD loved Devotion and Stoneskin on heals. :>