Inspired by a photo, I attempted to do a sample of each Langstichheftung (longstitch) binding style descriped by Szirmai. The three different structures he describes (in my photo, left to right) are the archival sewing, and the independent longstitch sewing, and the all-along sewing with change-over chain stitch.
These structures seem to be typical of the medieval limp leather bindings. Here's the photo that I started with. My attempt at the extra interwoven sewing created a rather thick and bulky pattern in comparison, but perhaps mine will look more similar after 400 years!