Travel shoe bags + technique: a finished opening in fabric

I recently bought some shoes that came in a half-box inserted into a reusable shoe bag that looked something like this. I thought it was brilliant and really convenient for both travel and simply carting an extra pair of shoes somewhere. No more dirty shoe soles contaminating your clothes (have you ever thought about those public bathroom floors you walk on? Probably worse in the men’s room … let’s not think too hard about this.) I’m about to travel cross-country and decided to whip up a few bags for my shoes. I previously made a giant drawstring bag to throw…