Im lvl 31, so I cant choose from the whole variety yet.

I had Qyzem around most time(Infil specced) equiped him the best way possible but having the male healer around with no equipment to speak of , he qyzen seems not to be the best choice.

Soon I'll get the sharpshooter and now I have to decide which to pick and equip properly

Any Advice?

While you're leveling, I would either use Tharan (the healer) or Zenith (the ranged DPS). As a tank, the heal comp is amazing because having him around can let you solo many random champions and heroics while providing you with negligible downtime while doing anything else. The DPS comps (specifically the ranged DPS comp because he has better AoE capabilities which is great for leveling) will help you kill faster, though you'll have some degree of downtime and won't be able to solo the random champions and heroics most of the time. Either way, the tank companions (Qyzen and Iresso) are pretty much completely useless to a tank: they're squishy and their damage is painfully low even in their DPS stances.

I would just pick either Tharan or Zenith to run with constantly. Either will serve admirably.

When rolling a tank, there's two big "schools" as far as choosing a companion goes: You pick a DPS or a Healer.

If you choose the DPS, fights will end sooner and will require a bit more of attention from you. If you go with a Healer, fights will be quite longer but almost a sure win, also you will spend less time resting after pulls.

I personally like to go with the DPS option when I play my Jedi Guardian. Kira's DPS is great, and I'd rather rest a bit after the fight than spend several minutes on each damn pull.

In your particular case, as a level 31 shadow, you pretty much have to choose between Tharan and Zenith.

Theran. Definitely go with Theran. For his liberal use of interrupts alone- I always go with Theran because none of my other healers have used so many interrupts before and I love it.

Plus. Occasionally catching sight of Holiday is just flat-out funny as heck.