Almost full chamber of split oak, mostly dry, 11:30 Friday night. I went to bed and woke up 7:30 AM Saturday, a bit worried to find only 1/3 of the wood consumed. The wood got caught up on the sides and the solid fuel was burning on the side, like a cigarette. Good heat on the top, maybe 300 degrees, lasted until well past noon. At 1:30 I put in more wood in a verticle position with lots of room to look down between the logs. Then I cracked the lid and let it rest until air rushed in from the down draft, ignited the new fuel (maybe 15 minutes), closed it, and reexamined the burn chamber about 7:00 PM. Four logs were charred in the corners and I put in two new pieces of split oak.
My theory is that I'll get more heat from wood in that if the burn heats the top and all the sides of the burn chamber without a dense mass of corn, pellets, acorns, or cherry pits insulating the sides of the top like fire bricks do in conventional stoves. If the things are not tightly packed together, more heat gets radiated, corrugated steel or not.
By the way, I've burned for 3 weeks now and I have only emptied the ash bucket twice. That should leave me time to wash my plate glass window and go to church on Sunday.