Could someone point me to a thread that details how well a BK heats a drafty house on a long burn? I know it can achieve insanely long burn times but I'm not sure if it's while heating a home to 40,50, 60+ degrees.
This is more or less the thread for that. As has been noted, "it depends". The stove is only one piece of the puzzle. How many sqft are you heating (easy), how is it laid out and where will the stove be in it (hard, subjective), how well insulated, closely related but not the same, how well sealed is it, how warm do you want to be in there and what ambient outdoor temperatures are you expecting.
If you have a brilliantly insulated house and a five year old who leaves the front door open, your brilliantly insulated house isn't very well sealed.
In general I expect you will find a sort of consensus range of stove sizes that should be about right in your application. From there, I would tend toward the largest firebox that makes sense, without going overboard. So for instance if the general range for you is 2.1 to 2.6 cf firebox, I would look at the 2.1s and 2.2s just to see, look real hard for something that seems perfect in the 2.5-2.6 range, maybe look at 2.8s, but not buy a 3.0.
I have no idea what size stove you need.
FWIW I have an Ashford 30, in the 1200sqft upstairs of my house. Downstairs I got another 1200sqft maintained at +55dF with my oil furnace. 2x6 construction, state of the art vapor barrier and multipane windows when the house was built in the 1980s. I have gone bananas plugging air leaks. I do not need an outside air kit (OAK) for my stove yet, but I fell like I am getting close. Most of my remaining air leaks are downstairs. My stove wood is magnificent, I am running birch at 16% MC this year and spruce at 12%MC this year. I have no elbows in my 14 foot of stack.
In shoulder (for me) season I can get 18-24 hour burns out of my Ashford. Does a burn end when the coaling stage starts, or when the coaling stage ends? At the other end of the scale, with overnight lows near -40dF and daytime highs around -25dF I run a full load of birch at bed time and another before leaving for work, and when I get home from work I rip out a full load of spruce in about four hours before reloading with birch around bed time.
If I was seeing -55 to -60dF on overnights and -30 to -35dF for daytime highs I would probably have to add a fourth load, a second load of spruce around 2AM to burn down after the bedtime birch but before the leave for work birch. Thankfully even in severe winters I only expect 15-20 days like that.
No matter what fuel you are using for heat plugging up most or all of the air leaks you got is going to save you money- and it can be a LOT of money leaking out those holes.