Rather than a bail, which of necessity involves adding holes (stress risers) to the boom, use a strop around the boom. This can be made of "seat belt" webbing or similar. On a much larger boat
, I use three wraps, hand stitched to join the ends, and a D ring to attach the vang shackle. A lashing or small strip of metal can be used to keep the strop from slipping along the boom under load.
Inexpensive and easy to make and install, no point loading on the boom.