Drilling for stitch holes would've been much easier if I'd had a drill press, as holding a heavy power drill stable while pressing it down via a thin metal rod was precarious, and I broke one drill bit in trying to do so. The size of needle and artificial sinew I used worked best with a 5/64-inch bit. Not to mention a drill press would've allowed the holes on the back side to come out in a neater line.
On the other hand, I soon found that the leather edge on the back was a little further back than on the front, so with the power drill I was able to angle the holes in slightly.
at least one example, a row of dots lined up with it. Such a design might have been appliquéd or done in hide glue paint. Although there's no way of knowing, it's possible that the gorytoi at Persepolis once featured such decoration as well.
I worked up the design on mine lightly in ink, with a little calculating of the available space for each square and measuring to keep the dots exactly halfway between the squares and the gorytos' edge. The paint would go a little bit over the lines to cover them up.
At this point, the bowcase would be functional and ready to take to the show, but not quite finished to the degree that I would like.
To prevent the fit over the bow from being too sloppy, the seam should be no wider than necessary, so some trimming can be done at this stage. I can't say I know for certain what a good width would be, as mine didn't turn out with a good precise fit anyway, but a quarter-inch seemed about right for strength.
Mark the seam as above. Using more ink is fine, since it won't be visible on the finished cover.