The surface veneers are made and baked on the top of the glass form.
Two sheets are cut to the shape of the earring veneer: a textured sheet that will become the back, through which I have cut a small slit so the clip-on back can slip through, and a plain sheet that will be sandwiched in the middle, the same thickness as the metal back of the clip-on, with a cutout window that is the shape of the back of the clip-on so that it sits embedded smoothly. Slip the clip-on back through the textured sheet, rotate into proper orientation and set into the cutout on the second sheet. Gently press the two sheets together.
These backs are baked on the INSIDE of the same glass form. The difference in the diameter of the form shape is only 2 times the thickness of the glass, which is negligible, and the veneer and the two-layer back piece fit very well together:
Scratch the surfaces that meet together, on the inside, with a needle tool, apply liquid clay (thin layer), edge with a thin strip of black to give a nice finish, apply your signature, rebake, and you're done, with the clips nicely embedded in the back.