Earlygame Assassin Archetype

I have a level 55 assassin right now and while acrobat is fun and strong I run out of mana in like 2 seconds because I'm using a speedleveling build rather than a mana regen build

Whats the strongest assassin archetype for my level (i'm running dungeons not grinding mobs because thats lame and boring)

And because its mainly bosses I'm fighting I'm looking for the best single target killer
Right now I'm a mix of all three archetypes going vanish and then planting the three smoke bombs on the boss and running away

 

There's not really a strongest archetype, but based on what you're describing, Shadestepper is probably best for 1v1 especially if you're trying to kill bosses (if mana is an issue you can try going for a melee one instead, works well with Shade). Additionally, Trickster isn't too bad as it helps with survivability and gives you some AoE but that does kinda require decent mana too. Regaining mana as Acrobat is significantly improved in the late game due to Jasmine Bloom but you definitely don't wanna combine Vanish and Acrobat because Vanish on Acrobat is absolutely useless since you'll be airborne and out of enemy range (not to mention the moment you hit an enemy you leave Vanish)