I mastered every job for every character, that way they could all go bare and have as many stat bonuses as possible for the final fight.

I've never heard of this "stat bonus as you level up thing." Are you sure? I never noticed it. It's all cumulative as far as I know. Magic ups for mage masters, hp ups for monk masters, speed for theives - when you go bare they all add up depending on what you've mastered. A bare character knowing everything should have the best possible stats for his level.