The pin-clip set up has held up well. I originally had 5/8 bolts that have worn down to look like 1/2, so that is why I made the new frame with 1/2, which has been holding up well. You know, you can order bolts in all kinds of strengths. Mine are just regular old bolts you get at the hardware store. You know, the size and kind that hold your house down to its foundation. I did tighten up the clip, which was easy to do.
Email me if you would like a PDF of how to do all this. It all weighs around 40lbs, scratches your vehicles less, and doesn't rust.