Thickwall vs Flaired bottom tubes?

I’m not sure why a thick-wall cylinder would provide more length gains. The main difference is going to be comfort at the base. One isn’t going to provide a different vacuum than the other.

I like the thick-walled tube (LapDist) I purchased about 6months ago. The base is really confortable and like the fact that it has the same girth throughout the tube. I hope to buy another tube shortly if I like my gains in Feb. if not I will use it another 3months. I have never even come close to having my balls sucked into the tube and it was one of the rpimary reasons I choose the Think-Wall tube with the flared out base so this wouldn’t happen ever. I guess it could if you got a tube much bigger than you actually are then it could happen. But if you probably want too see gains I would choose a tube 1/4-1/2in bigger in girth than you are now.