The shako top is on (looks like government contract work.) Here is how to make properly-spaced, straight stitches in thick leather. At right is a saddle maker's stitch grooving tool. It removes a tiny line of flesh at a set distance from the edge by adjusting the L-shaped bit.
Next to the groover is a marking wheel which leaves perfect dimples, seven per inch, for the awl. A wet sponge keeps the marks permanent. Finished, it looks like this:
The shako's back band already had a top groove for decoration. While not strictly needed, the bottom groove helps guide the marking wheel. If this were an external seam it would keep the stitches straight and even. Time to attach the lining and treacherous peak.