You can do a tuning plate or do something that would be the equivalent. I would try a 6 inch angle iron centered over your burn pot. Plate off each end so the heat gets cupped in the V channel. If fairly level to having a slight incline away from burn pot will direct heat more to the tail end of cook chamber. You could drill some heat reliefs along the run but it might do better retaining the heat to even out inside temps. This might work better with the pellet burner as compared to plates. You might have to add some flanges near burn pot to get more heat directed into the channel collector.