Hi, my name is Lou Wallman. I am a retired Banker from the NW USA and live in Ensenada, Baja California, Mexico. I have been smoking meat for about 5 years currently on a WSM, but am in the process of building a 24 x 60 reverse flow offset smoker on a trailer made from a propane tank. I am using the reverse flow calculator and circle calculator and have some questions if someone can help me. 1. The diagram of the reverse flow smoker picture shows the stack going down inside the cook chamber. Is this true and what would be the height above the cooking grates? 2. I have calculated the volume of the cook chamber, but one end is eliptical ( a propane tank), How will this affect the volume if I use the total length. 3 For the exhaust stack length is that formula ESV divided by 0.7854 x Stack Diameter x Stack Diameter? Thanks in advance for any help. This is a great group for ideas and learning.