Nylon Webbing Velcro Handle Pro Tip
Put some adhesive back slim-profile velcro (the scratchy side) on your rails before attaching your handle. The velcro will dig in to the nylon webbing of your handle and keep it in place so it doesn't slide toward the center. Cheers!
Velcro link: http://a.co/9qQhIe1
Handles: http://a.co/igGOYR2 (I converted these to velcro closure because the buckles are too big, but they are perfect size otherwise.)