Every 1-piece recurve I've had shipped too me from the bowyer came in a simple rectangle box (4-5 of them). None damaged yet. A Rose Oak Ultra Delight SE scared me a bit a few weeks ago. The end of the box was bent. I opened it in the post office in front of the staff to make sure it was ok. It was.
Personally, I've cobbled together rectangle boxes, mostly from rifle boxes. I have never had a 1-piece with a profile narrow enough to fit in PVC or Carpet tube that wasn't so large it cost a fortune to ship.
Definitely lots of packing material; bubble wrap the bow, double/triple the ends, and make sure the bow, with it's packing buffer, doesn't have any "wiggle" room.