I just sold two curves on e-bay. Went to local pro shop & got 4 compound boxes, two that would slide in the other two (made one long box out of two shorter ones). Wrapped & padded the bows with newspaper, then stuffed unused space in the boxes with wadded newspaper. Seemed to work real well, they arrived by UPS undamaged anyway. This is with bow unstrung, of course.
Regards,
Darrel