My smoker is no where close to those calculators...and it cooks like a dream. lol I would say about 15-20 degrees from front to back. It looks like on Franklin's cookers the stacks are 10" by about 6 feet. Live near Houston? I have a bunch left over. lol
Franklin's 500's:
http://s10.photobucket.com/user/SxFxZ/media/573147E9-8BC2-4703-85C5-215A25A2C2F7.jpg.html
Mine (10"x8' stack)
http://s10.photobucket.com/user/SxFxZ/media/3D85B57C-9510-409D-B0AE-486A6169B4DD.jpg.html
You better watch for low bridges! [emoji]128512[/emoji]