I have a Channing three installed in Oct of 2005 as well. I spoke directly to Alaska about the damper as I didn't understand "why" it was needed. On days when there is stronger draft typically either when its very cold outside or windy outside, the damper is likely to open more often and pull 80 degree air from you basement as opposed to 600 degree air from you stoker.
My alalysis is you'll get more heat out of the stove, and less up the chimney the more the damper is open. I didn't know how to set my damper up so I maxed it out so it would pretty much always stay open some. My theory, correct or not, is that the more the damper is open the more 80 degree air it will put vs. 600 degree air out of the stove, the former is preferable to the later for efficiency purpose. The only drawback from having the damper open too much, as I see it would be it might not draft as well as you'll coolling down the air going out the chimney. However, I haven't had draft issues, so my damper stays open. Do you know my ideas to be wrong? I guess my thoughts are an open damper should give you more heat and use less coal.
I haven't run mine on 3 for 24 hours straight, but I would guess that would use about 100lb, maybe just a little less.
My guess is that higher drafts would force more air through the coal and it might burn faster, however the amount it burns would seem to be dictated by the setting and not the amount of air (draft). The amount of air (draft) might take more heat out, or burn you coal more completely, but I'm guessing it wouldn't burn more in a given time.
You seem to have access to some knowledgable people. Everyone says stokers are less efficient at higher settings. I imagine part of this is that more heat goes up the chimney. To that degree I've been told not to use a heat reclaimer on them, presumably becuase coal is a low draft fire. However, here's a link to a website that sells one. If the "locals" say yeah of neah about it I'd appreciate you letting me know what their thoughts were. http://www.northlineexpress.com/detail~ ... A-1440.asp
Other than that I've likely going to install some floor vents upstairs. The basement is in the upper 70's and the upstairs is in the low to mid 60's. Hopefully I can get them closer in temperature.