I would put 2 pieces of fabric right side together and stitch a whole circle. Use pinking shears all around the edge or clip the curves. Cut the circles in half and turn right side out. Push out the curves and iron until they are perfect. You will now have the circle halves ready to sew along the front quilt edge. Lay the half circles on top of the quilt top and when you have then perfectly placed, stitch to the front. After stitching them on, iron them outward. The raw edges of the half circles and the quilt top will now be at the back. Smooth the backing fabric out and hand stitch the backing over the raw edges to finish the quilt. This quilt edge treatment I believe is called a knife edge finish?