Evisceration???

If you mean Dagger of Trials unless they have changed it no sch can't equip it. As seen on the popup

Love torque has been generally accepted as better for most Thf WS's. Even for mercy, Justice Torque / Einherjar Neck are likely better. Gorgets are good though.

If you are using evisceration you want to stack a lot of dex. If you're doing birds and aren't above 107 total dex, or mamools and not above 130, or if you can't switch to that much dex without gimping yourself, I'd stick w/ DE. G.Colibri AGI cap out at about 117 (50 points above g.coli agi) Mamool camp caps out alil over 140 iirc (50 points above xxx). What's important is it's the last 10 that matter. When your (dex - agi) is in the -/0 -> 39 range, about every 8-10 dex gives you 1% crit. 40-50 range, you get 1% per point of dex.

The evisc vs DE debate isn't currently settled. Bets still seem to be that DE wins. But the 100% native TP bonus likely gives +15% crit (on top of possible capped crit) to the ws, which is substantial. It's not a completely gimp WS if you have the gear to stack dex appropriately. Even moreso if you have X's knife.

As A owner of X's, Evis. does some mean dmg. But where it really shines as others before have said is in starting or finishing Darkness skillchains. 99% chance if you're in a dd pt, there will be a samurai. He is your best friend. Tachi:Gekko is your BFF. Thief's best source of dmg is from SA/TA or SATA wses. This doesn't just apply to just Evis., M. stab and Shark Bite can start or finish light. So do what you can to get the Dagger of Trials unlocked because it will make your thief that much better. Good Luck!