I have the propane version, 2 door and am about 3/4 done with doing the mod. I took the brace off of the smoker and am ready to cut out the back of the mail box. Unlike all the other pictures of my smoker that I can find on the internet, mine has 2 vent holes already cut into the sides. I was planning on leaving them alone and cutting out the back of the mailbox and directly attach it to the smoker. The usual mod was to cut a round hole in both the mailbox and smoker and running a small piece of pipe between the 2. For the smoker, I was hoping that I could leave the smoker's hole alone or maybe snip out the center pieces if needed. For the mailbox, recall that I am going to directly attach it to the smoker so no piping needed. So, would the shape of the hole be important ? Would it still work ok if I made a square hole that is slightly larger than the hole in the smoker ? The end result would be a mailbox with a square hole bolted to the smoker with a partially impeded round hole. I also have a battery powered 5" fan that I am going to mount at the other end of the mailbox to help force the smoke. What do you think ?