The color of these rondelle beads pulled at me so I purchased them, not realizing the tops and bottoms were flat-definitely not top quality. Easy fix...cover with a bead cap.
Consider using pre-textured sheet metal to make bead caps.
Bead caps are usually made of thinner gauge metal sheet. 26 gauge sheet metal works well to make bead caps, but 24 and 28 gauge will work, too.
The diameter of the bead is the diameter of the disc to cut. For 10mm beads, cut 3/8" discs. For 8mm beads, cut 5/16" discs. I do not generally make smaller bead caps, but measuring and forming them follow the same steps.