Both of the curves (inside and outside) will stitch the line the Arcs. It is easier to stitch in side a curve than outside the curve.
Westalee Design Arcs Templates available in 3″, 4, 6″, 8″, 10″, 12″ and 16″.
Set of 5 includes the following sizes: 3″, 4″, 6″, 8″, and 12″.