Suellen: maybe this will help
Lots of ideas.
I would be tempted to cover a small ball in plastic wrap, place the bowl mold upside down. Starting from the rim (now at the bottom) place buttons with very tacky glue, leave for several days to dry before removing plastic wrap and mold.
I made a small one w/ kids years ago. Blow up a balloon , glue buttons around letting all dry . Pop and cut away extra balloon. Works great🙂