I have a 12x12 alaknak with a Colorado cylinder stove.
While not a barrel stove, my

on the subject is that while a barrel stove is cheaper, the metal is thinner so 1) it will hold less heat, 2) being a big stove, it will burn more wood, 3) will not last as long as other stoves...
My thoughts would be to get a more efficient stove, or, get the double barrel adapter so it will hold more heat in.
If bulk isn't an issue I would look at a company called Vogelzang and look at thier cheap cast iron stoves.... They will hold heat better and last longer.
I wish I bought the next size up for my stove, but it is a pig and burns alot of wood and not very efficient