First I cut out the scales from the blanks. Then the 2 roughly shaped scales are glued together ( I use an removable spray adhesive). After that I drill the holes.
When this is done the spacer is cut out in the desired size. To make a hole in the spacer I put it between the 2 roughly shaped scales mark where the hole is in the scale, remove the spacer from the scales and drill the hole. Removing the spacer before drilling is important when you are using metal as material for the spacer. This can become hot and could melt acrylic.