Most can be duod. However, I would suggest using 'real' sub jobs. Just give up on coins for 1 run and go with a setup you would use to kill any other hard mob. Thf dnc isnt capable of tanking anything hard and thf/nin you wont have nearly enough cures. Ideally just bring a mage+melee and played properly and defensively should be able to down any of them. Or a bst :P
Ive done Quibetwhatever as Thf/nin+rdm/whm pretty easy. So long as you dont get any links (which is only a prob for him since hes not safe in a tower) and the bst/smn/drg one (gotta sleep that avatar). The mobs really arent that bad, just have to watch out for their dangerous 2hours. If you get unlucky with 3rd eye down when he EES you could be pretty boned. Sam/Nin+Mage would probably be much, much safer. Sam2hour can spam that AOE move 2handed fomors use, but can blink with shadows. Similar with Drk 2hour. Shadows basically stop all his 2hours youd be facing, just grab a mage if possible. Otherwise you will be rolling the dice with 3rd eye and relying on 2 /dnc for cures, and a thf that is likely to eat it if they get hate. Do-able probably just to get your attestation even if it takes a while, but you are going to need to be safer and more efficient to get teh 5x kills done for the later trial in 1-2 runs unless you want to just grind at it day after day.
Aanalaty, Mithra of San d'Oria
99Thf/99Drg/99Rng/95Pld/Secret Job 92
Maat-1/1 Thf Meleed (pansies steal)
Some of mah gearz: http://www.ffxiah.com/player/Lakshmi/Aanalaty#item-sets
Join 'People Against The Heart Snatcher' and help put Thfs on the right P.A.T.H.S.