Surviving wasn't much of an issue with MBD, shell, and wall up and Y'shtola's burst, although my damage output kinda sucked on D250 with only OK's faithga despite having bursts for all of my mages. Ashe did ~15k ixion casts during burst mode, but vivi and serah were only hitting around 8k on their AoE commands, so I definitely think trying to work in a 2nd faithga would make things go a lot better.