Smoker air intake and exhaust sizes.

I am working on a cabinet smoker, and I am confused about the intake and exhaust requirements. My smoker is 24 X 36X 52 inside 44928 cubic inches give or take. Is there some formula that I can use to figure air flow requirements? I want to put a charcoal maze inside it if I can so I dont need an external fire box. Does the smoke need to flow through fast enough to not get stale? I tried to use the calculator but it is for external fire boxes and I don't think it will work for my application. If I have to, I have a small boxwood stove that I can use for a firebox if this doesn't work and I end up making it a stick burner. I really appreciate any help.

Thanks Bludawg! Can you tell me how you got those sizes?

I am going to close up every hole I'm not using so that I have complete control over air intake. I have a single 3" exhaust and it is off center on the left side. I would like to add another one in the same spot on the right side. I figured the area of a 4" diameter, and 2 at 2 3/4" would be very close to the same. the intake comes in on the right side near the bottom. I assume that when you say 3" or 4" you mean diameter, and not square inches?? Also I see in the calculator where it gives the length for the exhaust pipe, how do I figure that out? Trial and error? Thanks for the help!! I am itching to get the smoke rolling.

Thanks Bludawg. That does give me some ideas.