I finally got enough sap yesterday to do a 4+ hour boil and with 280 gallons of sap, I was able to get about 65 gph including startup and shutdown. Forgot to brush the flue pan before starting and it was third boil since it was brushed or I could have possibly done a little better. Running the under fire air wide open and the top wide open too definitely uses more wood in an hour but I can also get 20 more gph vs running with 80% top air and 20% bottom air. Not sure how much wood if any I would be saving running 20 less gph if any by the end of the day because of the much slower boil rate. I am firing every ten minutes running it wide open. Was running stack temps staying between 1400 and 1600+ after a couple of hours of boiling and it was eating sap if it stayed in those temps probably during best hour was well over 70 gallons.