Like Rob said, you got a big area there. I take it you have floor vents coming from wood burning?? 40 lbs is about what I go through in the dead of winter heating 2400 sq in a 250 yr old farm house, tightened up as much as possible. You're probably right where you belong use wise--in the dead of winter--I'd bet your basement was a lot warmer during this warmer weather??? You're good on ash vents & MPD in my opinion & that's the most impt. right here
This winter is going to be an experiment for you. We all go through it. I go through 3 to 4 ton of nut per season.I think if you crunch the #'s you'll find you will do pretty good with coal--I'm guesstamating--$75.00 per cord of wood unless you're doing TT loads & blocking & splitting yourself---nut in this area is $240.00 per ton + delivery charge--- I would continue with NUT, it's what's recommended for the 50-93 & I have real good results w/ it. Did you speak w/ Dean at Hitzer or go through your dealer?