Dzus fasteners are available from Summit, however that's not what I used. You are correct about the hinge in the front, but the rear of the covers are secured with stainless 1/4-20" bolts. On the left side, the bolt screws into an threaded insert that is pressed into the body, however, on the right side the insert spun free in the hole, so I had to pull it out and drill straight through the steel support underneath, and use a longer bolt with a nut. The threaded insert would have worked better had I bonded them in the glass, rather than just relying on the press-fit.
Dzus fittings would probably work, however, I chose not to go that way because dzus fittings are spring-loaded, and I wanted to be able to control how much pressure was applied to the plexglass covers. I don't know how good your covers are, but mine were not perfectly molded to sit flat on the fiberglass, and I didn't want them to crack. I also used a rubber grommet between the plexi and fiberglass to help control vibrations.
I suggest looking at some old racecars that have these headlights to help give you ideas.