Uncrittable, got a spell damage weapon, you're good to go <3 At least offtanking anyway, just make sure you have a priest for a fort buff and bring some offset gear for bosses you dont need to OT on.
I started off-tanking in about the same gear in Kara. As long as you're uncrushable, you can OT. Get a flask of Fortification, Stamina food, Greater Rune of Warding and have Blessing of Kings on yourself. You might want to get you hands on Bracers of the Green Fortress and the 15 Badge Libram.