As an engineer, years ago, I became quite fond of the term, shamelessly
plagiarized. Find a grapple and copy it. Worth your time to look around.
You'll do even better if you find two different models and take the best
from each.

Nearly all units like this have 1" pins. Use McMaster Carr W1 grade for the
material. I've not seen bushings on backhoes and loaders. I suspect you
won't on grapples either.

Karl