Here you can see a solid skull and a hollow skull made from similar amounts of material. The hollow skull is made from ivory polymer clay, and the solid skull, which is destined to become a bead that looks like a sugar skull, is made of white polymer clay. Both beads started from balls of clay which were approximately 1/4 inch in diameter.
When your beads are the correct shape, gently enlarge any holes you need for candles, beading wire, etc, and bake them to cure (polymer clay) or allow them to air dry while still on the skewer or pin. If you are baking polymer clay beads, set them on a bit of polyester batting before you bake them so that they will not have any shiny spots where they touch the baking foil or tile.
Remove the pin or skewer after the beads have cured and enlarge the hole with a drill if necessary.