I cram every last stick in all the way to the top if I need to. The frame around the cat is robust, and you don't have to worry about tubes and baffles. It can take some abuse. BK is pretty honest with their advertised firebox sizes. You can use almost all of it.
I agree, if you get the attic properly insulated, a Princess/Ashford/Sirocco should easily heat your place while giving you some pretty good burn times.
A few hundred dollars more to get several more hours out of a load of wood, sounds like a good deal to me! They are a higher priced stove and have the extra performance to warrant it. If you don't care about the better look of the Ashford go with the sirocco. The extra expense is simply for the cast iron. I heat with only wood, I would spend that extra $400 in one month if I turned on the electric heat. I save so much money perhaps I look at it differently.
I'm very curious to know if the Sirocco 20 would be sufficient once the sealing/insulation is better.......not necessarily done, but just better. Done may take a while. We only get a few days below zero most winters, but man, it gets cool in the house and the stove just keeps the house in the mid sixties at that point. I have other heat I could use, but my wife says to not bother.....we'll be fine. Gotta' love her for that, except I get chilly and I don't like chilly. I do like chili though. I love that webby has the ability to try all these different stoves and report on them, but I don't have that luxury, so any money spent really needs to be spent wisely. When I was still working, I would not have hesitated to get whatever I wanted and maybe even swapped and lost money on the transactions, but that kind of money isn't available now, so I need to be keenly aware of how it's spent. I'll make the decision when the time comes, but in the meantime, I'm living vicariously through those who get new stoves, and vacillating as to which way to jump. White men can't jump though, so I guess I'll hop.
Took some outside measurements on the Ashley and it's almost the same as the BK Sirocco if both include the front ash lip. One of these days, I'll clean out the stove and take some good closeups of the interior and the air "manifold". See what you guys think.