I'm currently building a side firebox horizontal smoker and all my numbers have been working out based on Dave’s calculator. I just have a question regarding the chimney. I understand the need for length to obtain draft, however is there an issue with going with larger diameter pipe/length than what is required based on the calculator? Case in point.(based on the calculator), if i choose to use 3.5" inside diameter pipe for the chimney the calculator gives me a length of 16" (above the CC). this is obviously to short. If I simply add the additional 20" in length will this cause poor draft characteristics? I’m almost thinking it may cool off to much prior to leaving the chimney but I'm looking for someone who has experienced this first hand. Or can provide insight. Smoker specs: CC - 16” dia, 48” long FB – 16” dia, 18” long Thanks.