Q: Do multiple instances of Treasure Hunter in a single party increase the chances of a drop? When exactly does the effect of Treasure Hunter take place?
A: When more than one member has Treasure Hunter, the player with the strongest version will have theirs take effect for the party. The effect comes into play as soon as the Thief generates enmity from the target enemy. Even if the Thief dies, the effect remains.
I would assume the hand you're wielding the THF knife with becomes indifferent, based on the fact that the THF does not need to get the killing blow. But for the sake of the argument, let's say you do need the killing blow and that the TH knife-wielding hand does matter. If you were to get the killing blow with the offhand (non-THF knife), the argument stipulates that you wouldn't get the TH+1, thus it would be better not to dual-wield at all.
[quote:1gr3x9s9]the highest level of TH to gain emnity on the mob is the one recorded, and after gaining emnity you can die, zone, change jobs, whatever, and that TH effect will still be in place.