Step 5: Trim sole
Trim the vinyl sole so it's about the same size as the edge of the fleece bootie. Again, not rocket science - there's room for fudging here.
I first tried leaving a wide margin and folding it up and over the bootie's edge, but that didn't work. The thicker edge caught as Corvidae walked, and she scraped her feet, wearing through any fasteners (upholstery thread, etc) I had used to stitch the edge down. They quickly flopped open, and I had to do an emergency trim. It's faster and easier (not to mention more effective) to just trim to the edge of the bootie.