Those are really nice catches, where are they from? Anyway those catches wont keep the sides of the bonnet in line with the side panels, they are good for holding down but not locating. I saw an ali bonnet on a kit car that was held down with straps and the guy had put a couple of tapered pins in the top chassis rail looking up on each side. They passed through the bonnet return underneath purely for locating purposes ,all the straps had to do was hold the bonnet down , the tapered pins kept it in place.
Bob
Edit. Something along the lines of this x4 but with a bit more taper. Screwed into a rivnut on the top rail would do the job
http://www.xionglian.chinafastener.c...05115119_X.jpg