I have a offset masonry smoker that I built about 18 years ago. I am upgrading the doors (CC & FB) and enlarging the CC. Here are my Feldon's Calculator data: Link to BBQ Pit Calculator My CC:FB sizing appears to be ideal. My FB/CC opening is 33 square inches, rather than the Feldon's ideal of 50 square inches. Any opinions on how that might affect things? Other threads I have read suggest increasing the Feldon's recommendation by 50% - and in that case I'm less than 50% of the recommended size. With the smaller CC in the past, my smoker seems to have worked well - although I have no experience with other smokers. I will be making new FB intake dampers on my new FB door. The Feldon's recommended size is a total of 18.75 square inches. YIKES! I have only had a two-inch pipe as an opening in the past - and I usually had to damper that down to almost zero to keep the heat down. What on earth do I want almost 19 square inches for? Now I did have to open my door slightly when first lighting the fire in my FB - but once it got going, I'd have to almost close it off. I did not have any high-up damper for the FB in the past - only the one 2-inch pipe down at the log grate. I do plan on putting a vent up higher on the door - but not sure how big to make it. Any thoughts would be appreciated. Terry Farrell Tampa Bay, Florida The first three pictures below were taken before new mods. The last picture is the dome for my CC expansion.