I etched both sides of a 16 gauge circle of silver and enameled it.  Then I made a wide bezel that was about 2 mm too large in circumference and tapped it into a cone shape using a large dapping ball held in a vice as a form.  Then I marked and sawed

I etched both sides of a 16 gauge circle of silver and enameled it.  Then I made a wide bezel that was about 2 mm too large in circumference and tapped it into a cone shape using a large dapping ball held in a vice as a form.  Then I marked and sawed tabs around the larger edge, folded them toward the outside to get them out of the way, and then used a mizzy wheel and a file to remove about a mm so the edge would be about even with the other side of the enameled piece.  When it fit just right I folded the tabs back up to "straight", finished polishing and smoothing edges around tabs, then folded the tabs over the enamel piece.  See "Nicholas, other side" to see how it looks...and that the tabs are long enough to fold over the edge.  Is this clear as mud??