So I have these three old, unused propane tanks on the property. They belong to my in-laws, but I have been given permission to cut one of them up and build a smoker out of it. (Disclaimer: yes I will contact a professional propane tank technician to evaluate, drain and render safe for cutting before I do anything) The first one is probably in the best shape, and will likely be used again. 200-250 gallons I think, it's about 8 feet long and maybe 3 feet wide? Apologies for the lighting and shadows. There also seems to be an ant colony living in the valves under the orange cap. I think this one would be the ideal size, but it is in the best shape and will probably be used again for propane. The second one is smaller, a litter shorter and narrower, maybe 6 feet long and 2 to 2 1/2 feet wide, but the hardest to get to. Judging from the size compared to the first one, I think maybe it's in the 150 to 175 gallon capacity? The third one is the biggest. It's maybe 6 or 7 feet long, but a good 3 1/2 or 4 feet wide. Looks like it could be close to 300 gallons. It will also be the easiest to get to and remove as it is not covered in brush and vines. My goal is to build a large smoker that I can use for larger events, like weddings and social functions, maybe some competitions. In fact my brother has asked me to smoke a bunch of pulled pork and ribs for his wedding in June of 2016. So I figure: instead of wasting a bunch of money renting a smoker, why not just waste a bunch of money and build one and then have it to keep? So, I want to build a reverse flow smoker with two levels of slide out shelves in the main cooking chamber and a vertical warming/cooking chamber over the firebox. I would like to be able to smoke up to 8 briskets easily and a dozen racks of ribs, all at the same time. And it will be trailer mounted, probably with a smaller grill for cooking a small number of hamburgers and hot dogs to keep me and my crew alive while I am smoking the real food. Hopefully when my father-in-law gets in in a coupe of weeks we can tackle these propane tanks and get them into a position for better pictures and a thorough evaluation and measurements. I think the 3rd tank may be too deep to really use effectively. So the smaller one may be the one I end up using assuming it is big enough to do what I want with. I would appreciate any insight into which tank to chose and why.