Start with Osmose>Osmose>Osmose till you see 1's. Slowly dps down to 60% as you add orbs for the Titan and Lak summons. When your at 60% unleash holy hell and burn him down as fast as possible.
After his mana is drained he won't do any magical damage to you, its all physical. This is where a cover tank comes in. WoL, EV or iNichole+100% Evade unit. With the iNichol setup you'll take virtually no damage above 60%. If you use WoL or EV you need to break his ATK. His magical damage is tied to his MP level, he won't replenish MP till after 60%.
Confusion resist on everyone through items/materia/traits if you wanna 5 man it. Ilias is good if you don't gear for confusion.
From 60% to dead you want as much ATK/MAG, Imperil, chain and finish as possible.
My first kill was iNichol, Soliel+2 (100% Evade), Ilias, Tilith, DV and Orlando; This was a longer fight
My second kill was iNichol, Soliel+2, Ilias, DV, Luneth and Orlando; Prolly 8 rounds for summon orb farming.
My third kill was iNichol, Soliel+2, Ace, OK and OK ; This was a 2 turn fight..
No healer is needed if you have the deeps.. It's a DPS and mechanics check.