: You can make a simple jig for drilling your stitching holes from a scrap of
: wood that is 5 to 6 inches long. Decide how far from the edge of the
: panels your holes are to be. Let's say 1/4 inch in. Drill a 1/16th inch
: hole in your gauge stick that is 1/4 inch from one edge. Now drill a 1/8
: th inch hole 4 inches from that first hole, and also 1/4 inch from the
: same edge as the first hole. Tap a small (4d or 6d) nail into the 1/16th
: inch hole so that it projects about 1/2 inch. Drill your first hole at the
: center point on your panel, sitck in the projecting nail on your gauge,
: and the open 1/8th inch hole will serve as a guide for your drill bit.
: After you drill each hole, move the gauge along putting the nail in the
: most recently drilled hole. After you do a bunch of holes, say a dozen, go
: back to the center hole and start working toward the other end. Then start
: in the middle of the matching panel, and repeat the process.

i think this would work best only if the 2 pcs were symmetrical. if not, the holes are not the same spacing on each side, and the accrued error might be a problem. it will depend on how differentially curvy the adjoining pces are. a multi panel will be less of an issue than a 4 or 6 panel. somewhat design dependent. (i also would imagine that the nail spacer should be as close to 1/8")

i like the thin batten approach, marking ea hole as a 1/4in perpendicular to the tangent and using the same gauge for both sides.