@Spicyryan Idk about you, as I can't say what you do for bosses, but whenever I go, I have everyone get TP wings and drinks, and Fanatic's Drink. Fanatic's lasts for a minute I believe, which is plenty of time to stay alive without a healer. As such, White Magic is not AS detrimental as it would seem.
Though if you get JAs locked, you're screwed from the start.