I'm currently playing a Sith Assassin Tank as my main, and it's practically full 186 (Dread Master) gear. The only thing that I am currently missing is a hilt for my main-hand.
With that said, I am using the Dread Master Relics of Fortunate Redoubt and Reactive Warding.
My current stat budget is as follows:
This includes the extra defense from the Prototype Nano-Infused Fortitude Stim.
As far as the tanking builds and sets go, I do tend to change augments from time to time, in the gear, to adjust to different fights in the operations, same for the tanking build. However, for Dread Palace (Nightmare Mode), I did the entire instance (including Dread Council) in the "famed" Hybrid Tank Spec.
I hope this helps.