I'm starting to build a rotisserie smoker from a propane tank that's 36" in diameter, and 48" long. The firebox will be roughly 1/3 the size of the cooking chamber. I've been smoking for about 8 years, but I've never had a cooker this big, so I am just curious as to how much charcoal (I don't always have ready access to wood...) I might want to start with? Does twice the size mean twice the fuel and so on? Any info. would be great!