Im in the process of building a smoker on a small trailer. I need to decide on how big of a cook chamber I should use, I could build the cook box out a of a large propane tank thats 4ft long and 15 inches wide, or I could build the cook box from an air tank thats 4ft long and 20 inches wide, or last of all I could use the air tank thats 5ft long and 20 inches wide. So my question is if I use the big tank for the cook box, will I have to use alot more charcoal to heat it and keep it going, than If I use the smaller tank for the cook box. The majority of the time I cook a pork butt and some ribbs for my family and some friends, but Id like to be able to cook for 50-75 people once in awhile. But if I have to use a ton of charcoal just to cook one shoulder for my family then it doesent justify the larger smoker. I wonder how big of a difference is it from the smaller one to the larger one, in way of how much charcoal will be required.