Just looking at one of these, It seems to me that the current style of large covers would be prone to break easily right at the rivet point...is that pretty accurate?
I'm thinking that a simple design mod might make a huge difference on these. If the rivet point were beefed-up, and extended through the piece to the top, then force would be applied directly to the rivet instead of the thin portion of material forming the holes.
It also appears to me that the tabs on each side of the piece are incredibly thin. Is there a clearance issue on the holes these are inserted into, or could these be 2x-3x thicker?