Group setup doesn't really matter (though it helps to have a melee DPS for their LB I guess...still not needed). Above all else, the most important thing is to have a group of semi-competent individuals who are good at avoiding Weight of the Land, following the bomb patterns and not getting knocked off the edge. I've done this fight with many different combinations, including 2 tanks (one of them DPSing), 3 healers (imo harder than 2 healer setups), etc.

The fight all comes down to learning the ability rotation to the best of your ability so as to minimize avoidable damage that you take. As a BLM, focus on never getting hit by anything avoidable and use your cooldowns effectively. Perhaps a BLM could chime in on which sort of cooldowns are useful for which abilities (i.e. things like Manawall and such).