Becky's article should be very helpful for you. Mine are much simpler, but not nearly as classy.
I brought home the cattle panels in the bed of a friend's pick up. They were arched as they were loaded in, and stood up in the back of the truck. I hooked bungie cords on to them before pulling them out of the truck so they would stay arched. Once they were out of the truck I could easily carry them to where I wanted them by myself. And then adjust the distance between the sides by tightening the bungie cord. So - to answer your question - flexible enough to easily bend, when using the full 16' length, but they will spring back if not secured.
I use full panels, not cut in half as Becky did.
