In selling off my old one-piece recurves and a few hybrids, I have made custom boxes for shipping and it worked well. Here is the technique:
1. Get a box or two that are newish, in good condition, and large. U-Haul boxes are good.
2. The real trick is forming your shipping box to a new size and shape. I did that by bending the box using a 1x6 board and clamps and then bending the cardboard along the edge of the board.
3. After getting the box parts bent to fit, and taped together to make them the right size...
4. Bubble wrap the bow, and then use lots of tape to close your custom box up.
5. With this method you can make the ends of the box double thick to protect the limb tips...or you could make the entire box double thick.
-- This has worked well for me over the years.