I just count the number of times that the check pawl clicks during the cycle. Shut the power off to the stoker and turn the gearbox input shaft by hand. Pick a feed setting like 6 teeth, set the air at 6, and then let it run with your eye on the fire. If if starts to develop a large black spot, increase the air by one number and continue watching. If the fire is smaller than the burner plates, decrease the air. When it is all dialed it you should see about 2" of ash around the fire after 30 minutes of stoking.