I have to admit I have been recently able with it 75% closed get a long burn time . This stove and the learning curve is total trial and error. I was burning through wood way too fast but now I can use less and get more heat.
The Wife gets it shut down to 75%. I can't but she says I'm being impatient. If I shut it down and the fire starts to slow too much and look like it's going out, I open it back up. I guess I need to be a bit more patient and give the fire time to recover.