Hi Oldtool, yes glass inserted into the holes would work too, assuming of course that it was done after the bowl was turned.  I also thought of another alternative myself and that is to not even use anything to fill the holes, just turn the bowl and put the medallions into the holes and leave them like that.  Filling the holes with clear epoxy was plan A and I got tunnel vision I guess.  It would be easy enough to make 6 more segments for an a different approach.
Thanks for your comment.

David