Here ya go.
This was a photo taken by the PO for selling the boat. I don't think I have any with them closed. He used a thin strip of Plexi to thichen the edges for the hinges, and for the fixed portion screwed to the companionway board track. Plexi isn't that strong, and it's cracked at many screw holes, but I think I can do something a little different and still use the main panels.
The way it's mounted, I can insert the original board with this bifold system in place. They're kind of pointy and in the way when open, so I sail with them shut.
In the end, I think the upsides outweigh the downsides, so I'll probably see what I can do about making them better, as it's nice to be able to just open and close them rather then dealing with the hatch board. But I can also stick in the hatch board for greater security if needed (though a crow bar would be through it in two seconds).