I'll chime in (too bad I didn't see this thread earlier).
I too purchased A BJ90. Had a similar unloading situation - I ended up taking out the firebrick, baffles, grate, ash pan, doors (whatever I could to get the weight down) and brought into my downstairs piece by piece.
I finally was able to burn with it as odftwo weeks ago.
I grew up with wood heat, so I wouldn't call myself a novice
It's in my downstairs and I was going to attach to my existing ductwork, but haven't had time to do that yet. My entire downstairs is also living quarters, but open concept with a large stairway leading to the upstairs. The setup works amazingly well without being tied into the ductwork, so much so that I just may leave it this way!
By playing with both air intake controls (the one on the door and the adjustable flap on the draft blower motor) and the BDR, I was able to get easy 10~11 hour burn times. However, it wasn't a hot heat. If it's above teens outside, the low heat is plenty (and I like it hot inside my house, usually 80+) And I also noticed that dry wood is KEY.
If it gets a little colder, I'll adjust for a little more air, but useable burn time gets to between 5~8 hours on a good sized armful of wood. (I've learned to just leave the BDR alone around .02~.03" H2O) and just adjust the air intake instead (although playing with the BDR gave me similar results).
My home is built of ICF construction and is extremely well insulated and airtight (I do have a 4" diameter hole bored thru my wall next to my BJ90 for combustion air intake into the area near the stove though) although my home is only 1800 sq ft, I've got a lot of volume to heat (9 foot ceilings downstairs and 11 foot ceilings upstairs.) And I usually end up relighting in the morning, since I just let the fire go out iby late afternoon because it just gets too hot to sleep at night. I wish there was something like a BJ60 or 50, that would have suited me better - but I'm not complaining!