Don't Arrow Shower the mobs unless you're confident in killing them before they aggro to you.
Hunters are actually pretty useless in TI. Snipers are better with FAS, but still suboptimal.
Your best bet is to make your own party, since no one really cares what the leader's class is and, as leader, you can slack off.
As for what classes rock TI, pretty much anyone with a spammable AoE is fine, and the rest are for pulling or support. Sins pull, Knights pull and kill, Rogues pull and AoE with their copied skills, Wizards kill, Saders Sac and pull, Smiths buff, Alchemists aidpot and kill with their homunculi, Monks pull, Priests buff or kill with ME if the mobs are good for it, Sages do nothing/Scholars Exhale, Bards String and Dancers look pretty.
All bets are off as 3rd classes though. Everyone has an AoE so everyone can contribute to kills.