Personally, I think one of the best and most underrated tangs in this hobby is the Kole. I think most in the family will be OK, but the Kole is probably the hardiest.
With all due respect to our hosts here, this is a fish I personally would buy at an LFS. Mouth damage is one of their biggest issues (applies to the bristletooth tangs as a whole). I would go to an LFS where you can stand back and watch. You should find them picking at walls, rock, etc...if there is algae in the tank you should see their clear "pucker" marks. Good sign, IMO.
I like the bristletooth tangs in this sort of tank range because they seem to not be confined by the space. They are more interested in grazing much of the time.
And kudos on having, IMO, one of the all around best tank footprints
I love the 120. It does, IMO, limit some of the other tangs (personal preference, many would argue otherwise that a yellow or purple would be OK) but it is great for reefwork.