Roland, my guess from the start was that the wall is 1/4" thick. I also figured that the flat plates are 1/4" also, though now some might be thinner, I will play around and CNC mill a few different thickness of plates to see what looks best after distortion through the tubes. (by the way,thanks for working with inches... it makes my life easier, haha).
I have a feeling that Doc attached the lower disc to the drop point of the plutonium and rotated the bottle till it all lined up. It could explain why the lower plate is cone shaped, since the cone would make aligning it all up easier.