I've only ever seen HD foil in 12 and 18 inch widths at W'man's, Sam's, etc.
I don't use water in my 22.5 WSM, electing to use a clay dish instead. I do, however, wrap the pan (and said dish) in HD foil by laying two 36 inch lengths in a big X (for both inside and outside) to incase the entire bowl to make for easy cleanup. Despite the effort, grease/drippings still get thru the foil, probably because of pinholes caused by the crinkled foil. Still, it's easier to clean the wrapped pan than if it were unfoiled. I'd expect the same problem if water were used in a foiled pan.
SHole