At work, we ship stuff off for repair in Pelican cases.... It makes it a lot harder to damage the stuff (Air Canada has a forklift operator that has managed to prove that it is not impossible). For shipping a lens one way, I would put it in a plastic bag, into a small box with soft foam, and then into a bigger box with more padding.Basically just don't pack it like an idiot. The lens was wrapped in about one layer of bubble wrap (the small bubble type of wrap) and then put in a box with a bunch of those plastic air pillows. The box was a little bigger than the lens itself. When I initially took it out of the box, it was resting against one side of the box. By that I mean, a bunch of air pillows on top of it, but nothing cushioning one side of it aside from the one layer of bubble wrap it was in.
If it was me, I would use a box about twice as big as the lens, and I would absolutely entomb that thing in bubble wrap so it can't move around. The lens weighs like 6 pounds. If it's allowed to move around at all inside the box, it's gonna get damaged.