I can't speak to pure solo, but since you're dualboxing I'd suggest a WHM+DD combo. I did the whole thing from start to finish with SAM+WHM using Ulmia/Joachim/Koru-moru and had zero issues.
Trusts do a pretty good job of keeping up with buffs and debuffs as they wear, but I don't really...
trust... them with more important things like healing at a sustainable pace. DD trusts also don't do very much damage (prolonging your fight) and healer trusts don't heal the battlefield NPC's (who will be dying from the drawn out fight).
Support trusts do more damage by buffing a player character than DD trusts do by attacking. As an added bonus, you don't need to waste a spot on a tank if you're doing all the damage yourself. Bringing your own WHM also lets you keep your healer out of range of AoE silence, petrify, etc. Barspells, Cureskin, merited Shellra V, and empyrean legs Curaga will go a long way towards keeping you afloat as well.