One to be Feared/Ctownwoody's CoP 6-4 Experience

Okay, simply because I document so much else, I have decided to document my 5 runs through 6-4, which is accounted the hardest Mission fight in the game, or so I am told. Being only on the 4th Aht Urhgan Mission, I wouldn't know for sure.

The Cast
5 runs, only 8 people in my LS needing the mission, and having the help of 3 others who had completed it, we did have a certain issue with how to format it, but I will run down how I perceived the various jobs did.
 * BST/NIN (that's me): I pwned. I could have soloed Omega and Ultima!  Okay, truthfully, I did well.  I had a strong Accuracy build so I could eat the best meat possible.  I had good weapons: Wrath Tabar and Kabrakan's Axe.  I had Warm Meat Broth for my new favorite pet, Saber Siravarde.  The trick was the 20 Hi-Pots I got from a Hi-Potion Tank; they made me largely self-sufficient.
 * WHM/SMN: This is the best whm combination because the WHM will NOT be doing anything besides curing duty (well, until you get Omega/Ultima down to the last 5% and want to unleash Holy or a Banish-type spell), so the Auto Refresh helps immensely.  The real keys, however, are using Blood Pact: Ward during prep.  Depending on the make-up of the group, either Aerial Armor or Frost Armor works well.
 * BRD/WHM, RDM/BLM: We had one of these each run and it was great for help.  The main key is to have someone in the group that can keep mages going strong.  BRD or RDM will do that.  BRD can help the melees with Mambo and March.  RDM can Chainspell something, such as Drain.
 * PLD/WAR: Duh. Best tank possible.  Omega is fond of some funky AoE attacks that wipe shadows and has nasty TP moves that give Status Effects, so I shudder to think what a NIN tank would have been like.  Also, a double-Mambo, Bat Earring PLD/WAR can hold those Mammets almost forever.
 * BLM/XXX: We had one a few runs and it did very well for itself.  Enough De-buffs to help the RDM out, and great DD.  We defeated Omega once after a wipe using Operation: Burst (wipe, reraise, Burst to defeat without waiting), and almost did it again on Ultima (but timed out).
 * BLU/NIN: A key player on the run that won. This was expensive for him because he needed melee food, refresh drink, hi-pots for HP, and hi-ethers for MP.  However, "Head Butt FTW!" isn't a common tattoo for no reason.  Also, in a pinch, his Magic Fruit was a life-saver.  His de-buffs weren't that accurate, sadly.
 * DRG/NIN (/WAR): One run, he was /WAR. The run where we won, he smartly switched to /NIN.  Omega = death to non-/NIN melees except a PLD.  Too much time was wasted curing him and he was always the first to die, even before the PLD.  I'd beware the devastation to your pet that AoEs cause.  It was hard for him to keep his pet from dying, which restricted his 2hr ability
 * SAM + RNG: We had a RNG/SAM for 2 runs. Wow!  Spike-damage city.  In fact, he claimed he was too sexy for his gear, cuz he had the usual RNG problem (or claimed to) of drawing hate too easily.  But he was doing WS that topped 1k to Mammets with ease and was WSing Omega for 700+.  Aerial Armor or a Blink Band is a must for them, though, in case they do get hate.

The Supplies
Everyone: CCB Polymer Pump! Do NOT, DO NOT, Do NOT forget or disdain to bring one. This is literally the most important item. Omega unleashes his worst and most disabling TP moves near the end and Ultima has no AoEs until he starts using Super-Nasty-Death-TP-Move-of-Doom under 30%. Both also have a single-target, massive damage, hate-reset move called Pile Pitch that will destroy your tank's ability to keep it from killing people and running randomly all over your party. Also, everyone needs a Reraise (Status Effect) item. It will save you a minute or so per wipe, which translates to over 2% of your time. Tank: Tavnazian Taco, Hi-Potion Tank, Yagudo Drinks, maybe a Hi-Ether or two. Blink Band and Icarus Wing. Melees: Shihei cuz all of you are /NIN, Food based on gear set-up (either Attack food for accuracy-heavy sets or Sole Sushi for Attack heavy sets), Hi-Potion Tank, Icarus Wing, MP stuff if you need it, Pet-friendly items for DRG or BST. Mages: MP food (Rolanberry Pie or whatever gives you the most MP), Hi-Ethers (watch out for delay after using one before you can cast a spell), Yagudo Drinks (never be in a battle without one active).

The Prep Work
Before going into battle, everyone get the opening Cut Scene in Sealion's Den. You will do some scenes on an airship and then be able to move about the Airship. Have fun, check your stats under a level 60 cap, etc. Then exit the battlefield. Now, this is important: do not leave Sealion's Den. If you do, you will have to redo the first Cut Scene again, which costs you over two minutes, or over 5% of your allotted time.

The First Battle
I like to call this, "The Pwnage Revenege Scenario" for two reasons. First, the Mammets in 2-5 were horribly tough compared to your level then. They aren't that much tougher in this battle, but you are sooo much better. Second, you pwn them. You really do.

Strategy
RDM or BLM: Silence the Mammets as they get pulled to you. Then, if they aren't in staff-form, do a strong, single-target nuke. Dia 2 is also nice. Ranged-Attack Bearer: Pull. Set up an order. We used "Left to Right", meaning the leftmost one was pulled each time. This prevents pulling two at once. Melees: Pwn. You do that voodoo that you do so well. Random Melee without too many macros to use (was me as BST/NIN): Have a Yellow Liquid or two to start with and try to lock Mammets that get pulled into either Staff or Polearm forms. Sword has AoE TP moves that get annoying and the Hands-version can use Transmogrification, which makes physical damage heal it.
 * Tank: PLD/WAR can super-tank.  Get a Blinding Potion and two Bat Earrings and go to town.  Dodge, duck, dive, dip and dodge your way to the where the middle-most one starts.  The additional trick is that because they will all sight aggro you at the same time, their attacks will be largely simultaneous, letting you cure yourself easier.
 * WHM: Help the super-tank.

From there, just let the melees kill one at a time, don't woprry about healing except to prevent death, don't worry to closely about MP. Also, don't save TP. Unleash your best WS as soon as you get 100% TP. The goal here is speed-pnwage. Each Mammet drops 1-2 Yellow Liquid, so unless you had serious serious problems, you will have extras. After the battle, you will enter a holding area.