Thanks for all the great info!
I'll only be doing one drum at a time, so I don't think I'll need a tank quite so big as 15 or 20 gallons. Actually, when I put the drum in the round tub I plan to use (I think it's about 18" or 20" in diameter), it only takes about 5 or 6 gallons to totally submerge the shell. Is there an advantage to using more liquid?
Another thing I'm curious about is the placement of the anode(s). I'm sure the plating manual probably covers all this stuff, but I haven't order the LCD kit yet so I don't have all this good information handy. Can the entire inside and outside surface of the shell be anodized in one shot, or should I do the inside and the outside in separate steps? Will I need to reposition the shell with respect to the anode(s) throughout the process? If so, will the purchase of additional plates alleviate this need, or will that overtax the capabilities of the power supply?
I apologize if these seem like dumb questions!

I just don't want to go off and order a bunch of things I won't need, or have to place additional orders to get the job done.
Thanks!
Steve