Foxymom, here’s another idea…
If the pearl is nice on both sides, why not set a stone in the
other side to make it reversable?
Drill the pearl to fit a tube slightly smaller than what you
need to hold the stones. Then flare the openings on each end to
the right size for the stones plus metal. Insert the tube, and
flare it to fit the flared section at each end. Now you can set a
stone in each end. The tube won’t come out, as it will be flared
at both ends, and the piece will be reversable!
As for your question about what burr to use, I’d make sure the
walls of the tube are thick enough to flush mount the stone, and
then I’d cut the bearing with a tiny heart burr.
How are you attaching the bail?