I'm currently building my first smoker. I'm using a vertical 120 gallon propane tank that will be a horizontal reverse flow offset smoker. I've already cut the door and built a 24" x 24" x 24" firebox. The tank has a 30" diameter and 48" length cooking chamber. I'm using the calculator specs below: http://feldoncentral.com/bbqcalcula...46&fi=18,4,0,41.47,0.58&fc=11.87,16.78,110.59 My question is that I'm stumped on the firebox to cooking chamber opening. I've cut it 24" wide by about 6" tall, so it is inset a little bit into the round part of the dome on the tank. Is this going to work, terrible on that math part so some help would be nice. I've uploaded an image to illustrate what I've done already, hoping to run my reverse flow plate right off the top of the firebox along the bottom of my cooking chamber.