I use a 10cfm because that is what I have and most of the time I need to close it down some, in order to achieve the temp I want. On my Lg Spicewine I have to close the exhaust down a bit, maybe 1/4 for a better burn, that is with or without the air controller. I suggest you fire it up once or twice and try regulating temps to your liking, you may find you don't really need the air controller
Lg Spicewine on trailer
Weber charcoal grill
2 ugly drums, semi retired
Bbq toolbox, formerly Chargrill smoker
My wife has gas, its a Brinkman.