I've got another question. (of course). My Masterbuilt, 2-door smoker has (2) round vents for incoming air - one on opposite sides down low. It also has the vent at the very top back of the unit. I've not yet figured out what I'm supposed to do as a general rule? I play with the vent openings, but quite frankly, I have no idea what I'm doing. Do I open the 2 bottom side vents all the way, all the time and keep the top exhaust vent almost closed? Thanks!!!!