This is the best way I’ve found to bend herringbone binding. Use your half template and make a plywood form a couple of inches bigger. Put some legs on it to raise it off the table. Clamp the form to it, soak the herringbone and work it around the form using spring clamps. This holds it well and you can let it dry or hit it with a hair dryer and it will hold it’s shape nicely. The spring clamps keep it flat.
