i would like to see if the 55 hm would be doable in 55 columni which would put them on the same level as the 50 ones starting level gear wise. but that gear isnt no longer available.
It is not, but Rakata gear is available for very cheap at the planetary com vendor on Makeb.
Also the main hand weapon for 85 basic token is a steal, even though you'll need reputation to unlock it.
I'm seeing things from a tank perspective, but if the healer can go afk to get a beer out of the fridge during the mining Droid and Battle Lord Kreshan when I'm in full still in level 50 gear doesn't feel that ludicrously hard.
Bonus bosses actually all deal quite a chunk of damage to the tank, but this seems to be intended and sone of them actually do nothing else at all.