This rack.If you want to save some work and $'s.... The AMNPS needs a supply of air that doesn't need to be adjusted... See my pics below... I have covered over the lower holes partially.... I would recommend 3 each, 3/4" holes as shown... that should be good.... If you also need to adjust the air flow through your smoker, a separate air inlet for the smoker would work and that "butterfly" valve would be great for that.. BTW, I call that a "pie" vent 'cause it looks like slices of pie...The upper hole is to keep the smoke from swirling and cutting off oxygen to the pellets... or so it says in fine print....
thanks
dave