I don't like building a cage out of pipe. If I'm going to trust my life to it I think it should be tubing.
Why would you want something that is thinner and easier to bend? Pipe is much thicker and stronger. Or am I confusing the two?
At the steel yard I buy my material from they offer two round materials (3 if you include solid stock)
1) Tubing which is sold by gauge and measured by the outside diameter
2) Pipe which is sold by schedule and is measured by the inside diameter
All the tubing both round and square I have seen is thinner and we use it for our decorative rail and ornamental stuff. But for anything structural such as large gates, deck supports, flitch plates and beam supports we use the thicker pipe.
Are you referring to the way the tubing and pipe are built? There is always alot of confusion in how the two differ and I still don't know the true difference between the two and I own a small steel company.