I wouldn't recommend final wash of fb in drums for lots of reasons, not the least of which is that you won't get good flow over the back of the paper. I'm not sure why one would want to when the mural process is at it's simplest and most straightforward in troughs.

rc is easier, a lot cheaper and available over 30"....http://www.bhphotovideo.com/bnh/cont...G&A=details&Q=