Although the currently-available replacement late-type clip works perfectly well, it is not identical to the original. If you want to make your own or modify the new type, the following collection of pictures might help.
The design allowed the front of the hood to be snapped into place with the conical ends of the windscreen support posts automatically pushing the spring-load keeper plates open. As the hood frame went slightly lower, the plates sprang into rectangular-shaped cutouts, and the hood was locked in the down position. Each keeper plate was extended to form a lever that released it, allowing the hood to be raised. A small hinged safety tab was provided to lock the lever in the closed position, without which, as many units have suffered from weakened or broken springs over the decades, it could have vibrated out and the hood opened by itself.
When fitting the units, do check the slots in the windscreen uprights; the writer has seen several where the slots are no longer sharp, but rounded off from years of use. In the worst cases, the slots need welding up and new ones cut; those most just needed a little judicious work with a small, square-section file.
Over the page are details of the often-missing pair of leather straps that helped fasten together the hood frame tubes when the hood was down.