OK, followup time. I had all the materials on hand at home - I just linked to Velo Orange for reference. I eventually just did it flying by the seat of my pants, and it turned out pretty well. I made some measurements, cut four little rectangles of leather, pre-punched the holes with an awl, and dug up a blunt needle. The sewing, as with all my sewing, is somewhat rough. It is, however, effective and secure and so far they look good and my shoes are happier. I also learned enough to make the next go more accurate and easier.