Joe,
I've done these for period spectacles.
Not sure if Steve does it this way, but you can set it up for a tight friction fit of the lid just as it is slips fully into place by angling the bottom of the lid very slightly. You want the lid thinner on the side that slides all the way over the top and a bit thicker on the side that just comes into contact when the lid is almost completely over the top of the bottom piece that holds the spectacles or glass.