Unlike rivets on highly stressed metal structures, stitch spacing for lightweight S&G boats is pretty open-ended. All you actually need is enough stitches to hold a fair symmetric shape and to keep the edges in close proximity. Depending on the thickness, shape and amount of bending of the wood, that can be as little as 2 inches or as much as a foot. FWIW, in my experience most S&G boats actually have many more stitches than they need, especially boats with gentle curves.

As to why the PMD spacings are different, the manual sounds to me as if it was written for plans builders while the kit has been optimized for CNC manufacturing. If you're building from the kit, it's safe to ignore plan builders' steps in the manual that the CNC router has already done for you, such as spacing of the stitch holes.

Short answer - probably no addendum, don't worry, be happy. You're going to have a really nice boat sometime soon.

Laszlo

Thanks for the perspective, advice, and encouragement. Will do. Stitching going good   Buff