The Layline instructions I got with a strap I bought through them recommended this method. They also suggested using an eyestrap as the backing on the cubby side of the lip. I followed that advice and found the eyestrap quite handy for clipping a small dry bag to.Nicely done captainpete.
But you can also mount the strap a bit higher so that the screws protrude into the storage area. That way you can back them without cutting a big hole in the hull. When you go this route, you do have to be careful about drilling the holes just right....
I am going to change my method of mounting the aft end of the hiking strap based on these ideas--many thanks.
For old style, non-cubby Sunfishes, I still like the access port in the aft end of the cockpit for access to the backing material.