Hey guys I am new to these forums and I'm looking for some help. I am building a 20" by 52" offset smoker with a 20" by 20" round firebox. I am having trouble with the firebox to smoker opening. I have been on the Feldon site but I can't figure it out. Can anyone tell me how big to make the half moons? I am having a shop cut them for me so I don't know what to tell them thanks guys!