We’re using 1" strap (though no Velcro). We have found that tying a bowline at the end with a loop ~7-8" circumference with no serious twists is easy to fasten securely. Hold the strap by the knot with the loop pointing up. Grab the top of the loop and give it a half twist with the back side going [strIke]down [/strIke] up and the front side going [strIke]up[/strIke] down. Raise the knot to over the channel, with the flipped part against the “lower” face of the fingers. Bring the straps on either side around the fingers, and pull the knot into the gap between the fingers. Put in the retaining pin. Edit 2: See the attached photo mosaic.
Edit: This method should work just as well for a sewn loop.
