I am building a reverse flow smoker but instead of putting fire box on one end, I am putting it directly beneath the smoker. Because of this I am not sure how big to make my openings. If I run my numbers thru the Feldons BBQ calculator it tells me 7.22" dia opening for my fb to my cc. And i know that on a traditional side mount box that on my far end of the baffle it needs to be the same size or just a little bigger. But with 2 open ends on the baffle would you cut it in half or just make them both 7.22"?