At this point, don't bother. They applied a massive nerf to companions today, taking healing down by ~75%, and nerfed tank companion self bubbles while leaving in a bug where they have 0 armor or defense at 65.

It had been possible to two box most of the tactical flashpoints even at a lower level if your companions had a decent influence level. (I did the weekly quest of clearing 5 a few times with two Mercenaries/Commandos with companions at rank 20 at 60.) Now though after the change that isn't looking so good.