I was using a regular iron tank, the only drawback was that it wasn't wide enough for 32" barrels. I found a lightweight 8" flanged stainless cylinder at my local scrap yard. I then self-tapped the flanged end to the top of a pressure cooker I also found at the yard. I sealed the flange with JB Weld before I drilled the self-tappers through the flange. I modified a turkey fryer stand by replacing the burner with a high output wok burner, running on natural gas. I adjust with a ball valve, the output is so high I can make sure I never lose a boil. The tank is set up vertically, and can hold two barrel sets at a time. It's easy to remove the barrels by their hangers and hang them up to dry nearby. It works well in the basement, I also installed an exhaust fan and made a hood from a scrap wood frame and aluminum foil.
I started out using it for longer barrels, but found it so easy to use that I now use it for all barrel boiling.
Ken
