Well, after giving it some thought, I decided to use two of the Dzus fasteners I had purchased at B&B surplus at Oshkosh this year for latching the lid of the toolbox.

I made up a couple stiffeners for the lid from some scrap 0.040 thick aluminum.

Then made some brackets to rivet the Dzus nut to. I thought these were 0.063 thick when I was making them, but they turned out to be 0.040.

Since that seemed a little thin, I decided to remake them from an old Z bracket. I rounded over one edge to make the brackets prettier.

A bunch of cutting, sanding, filing, and drilling later, these are pretty close to being done. The center hole needs opened up to .250 and I need to position and match drill the blank flanges to the side of the toolbox. Of course these and the stiffeners, above, will get primed before installation.