Great questions!Yes, the mechanical thermometers do track right with my digital thermometer (double probe model). I generally only use my digital thermometer when I want to continually measure meat internal temperature as well as cooking chamber temperature. Otherwise the mechanical ones are more handy.I have another view of the side firebox of this Oklahoma Joe Longhorn showing the open side door with the butterfly damper location relative to the basket, but can't attach the image for some reason. However, there are 2 butterfly openings, one at the very bottom of the side door and one nearer the top. The lower butterfly opening is below the charcoal grate that the charcoal basket rests on, which BTW is the original charcoal grate that comes with the Oklahoma Joe Longhorn Smoker-Grill. So yes, one of the air intake ports is well below the charcoal basket, but the other one is nearer the top of the basket - but still below the direct-searing cooking grate that rests immediately above the charcoal basket. This 6 inch high charcoal basket fits perfectly between the 2 original OK Joe grates, and it does work very well. If the basket was any higher in the firebox then the direct-searing cooking grate would not be able to rest on its welded attachment rails, and would be too high. The charcoal basket is also properly located with respect to the side firebox opening to the indirect cooking food chamber - and I am using a home-made convection/diffuser plate inside the food chamber.