The following photos are the overlay for the heel part of the shoes that I did.
My purpose is to test the placement, spacing, shape and overall detail of the sequins, and this particular overlay won't be used on any ruby slippers. You will notice that it looks a bit different on the left and right side. The sequins on the left side of your screen resembles the pattern of the heels on the original ruby slippers.
There are two ways to add the sequins to the base shoes. Most people sew the sequins onto a fabric overlay in a round embroidery hoop and then attach the overlay to the shoe by either sewing or gluing. While some people prefer to sew the sequins directly to the fabric overlay which has already been fitted for the shoes.
Sequin overlay for the heels of Judy Garland's ruby slippers