It took me an hour to even beat the D240. Used Vivi (USB), GArnet (BSSB2), Beatrix (nothing), Eiko (BSSB), Kuja (BSSB1/LMR). I kept pushing phases too fast and kept eating Incubus Viral Smoke -> Incubus Doomsday -> dead. Managed to win in 17.56 eventually.
It took me an hour and 40 minutes to beat D280. Eventually dropped Beatrix for Freya (who has BSSB, but it's utterly useless in this fight) and debuff dances. Ran into the same problem really, where I couldn't get hastega back up after fucking Incubus Viral Smoke without someone dying. Eventually I got a good run, and was in good shape coming down to the end, but ran into Doomsday x2. Kuja was last man standing who managed to fire off a Dark Zone and win in exactly 30.00.
I managed to keep Kuja/Vivi both alive and scrape a 52% "victory" against D??? after an hour of trying.
Vivi (LM1+LM2)L R4 Chain Firaja, R4 Meltdown, Mag DMG+ RM (USB)
Garnet (LMR1): R3 Allegro Con Moto, R4 Valigarmanda, MM (SSB1/BSSB1/BSSB2)
Freya: R3 Enfeelbling Jittebug, R3 Heathen Frolic Sarabande, Ace Striker (no SB)
Eiko: R2 Hastega, R4 Curada, Gathering Storm (BSSB)
Kuja (LM2+LMR): R1 Hastega, R4 Dire Heal, Scholar's Boon (BSSB/OSB)
Magicites: Unicorn, Phoenix (+L8 Blade/Spell Ward), Famfrit (+L8 Blade Ward/L8 HP Boon), King Bomb (+L15 Mag Boon), Seraph (+L10 Dark Dampen)
Bio+Dark resist on Vii and Eiko, Major Bio resist on Freya, bio resist on everyone else, minour Dark resist on Kuja. I figured I'd be dead long before Incubus Doomsday showed up so prioritized Bio resist.
After having runs ending by not being able to get Hastega back up after Incubus Viral Smoke, I took the suggestion from someone on Discord to run more than one Hastega. And I was planning to shatter that second free copy we got recently, but it came in handy. It allowed Kuja to get Hastega up turn 1 while Eiko got to fire off a couple Curadas to offset some of the early damage.
Christ keeping people healthy in this fight without Eiko USB is hard. I thought Garnet BSSB2 had an AoE Heal + Summon command like Yuna, but it does not (at least, not one you can spam every turn). It's actually junk for healing. In fact, if it wasn't for the fact that her BSSB2 is my only Faithga for the realm, I would have stuck to Garnet BSSB1, since that has a healing command + Esuna! It came in very handy for the second Incubus Viral Powder (Unicorn blocked the first one) when I got Eiko and Kuja back up. But I needed to re-up BSSB2 around the 35 second mark since Vivi's damage was tapering off. Otherwise, she used Allegro -> Vali when she could.
I had trouble getting Vivi into trance in this fight. Either too much or too little damage. eventually settled on tanking the first 2 attacks and defending for the next two. Vivi wasn't capping with chain Firaja until the chain count got fairly high, I'm rather disappointed. Probably should have put Scholar's Boon on him instead of Kuja.
Kuja put in good work. Initially was trying with MM+Dark Zone, but then I switched to the double Hastega setup to help later in the fight. Used DZ first, but then realised I should use Dire Heal instead because Eiko was under constant healing pressure.
Against D240 and in earlier D280 attempts, I used Beatrix, but she's so goddamn slow and I only got to use her SSB once, and by the time she got to use it all the unblinkable stuff started coming, and I only have her BSSB1 so I replaced her with Freya and dances to reduce incoming damage. I have Freya BSSB but didn't bother to use it. If I had another proper DPS I might be able to go further, BUT I fear that incoming damage.
I could also probably go much further if I dived everyone but... nah. Not feeling it. I'll wait until I have better options for the realm.