Not alot of posts seem to go on anymore and i've never really written any sort of "Guide" before. But i would like to give it a shot, atleast to get the ball rolling if anything.
Ok, I'll start with the ideal setup for this and blm is included in this. I did a six orb run while on ninja and this is what i have learned from this. My Ideal setup would be: Whm,Blm, Ninja, Dragoon, War, War.
So 15 minutes is your time limit, when you enter the BCNM your first objective will be to seek out 4 "mini" Antlion(much like sheep in antlions clothing). They are more than likely "Easy Prey' blind/slow/para landed easy as ninja as well as sleep from blm. The mini antlion's "Pit Ambush" did right around 400dmg to a 95 ninja. Destroy the 3 and on the fourth you will want to bring it close to where the Main Antlion pops. You will have one minute from the death of the last mini antlion to damage/kill the main antlion before its phys/magic defense goes back up. On the third/fourth mini antlion melee's should be saving tp, and now is why i prefer to have a Dragoon in the party for this. Angon(20% def down) will go a long way depending on how he/she has it merited. Best would be 45 seconds. If you are unable to kill the main nm the first round just have the person with the most hate(should be the nin) just keep running away from it. The antlion will not move and will spam tp moves and draw in(should take no damage w/ shadows). Hopefully the dd's will be able to kill the four minis again and finish off the main nm.
The main antlions spawn location is in the crater heading towards your upper left hand corner upon entering the bcnm.
The main antlions Pit Ambush did almost a max of 1K damage and its melee hits were 3-400 dmg again to a 95 nin. Pit ambush ignores/wipes shadows. I personally just ran right to the middle to pop the nm and once there just casted Utsu Ni almost right after and was able to apply right after Pit Ambush. You can if you like, setup a SC and MB or just nuke moderatley on the main NM.
I will try to refine this later if/as needed. Like I said this is the first "guide" i have written (it was sort of rushed)and hopefully it can help some people or atleast give someone somthing to go off of. Please if you have anything to add then post it.