If it is a hatch that opens, take the above mentioned calipers and add 2 small round objects such as marbles (one between the glass top and the caliper, one between the bottom and the caliper) and measure the total thickness. Then measure the round objects and subtract them.
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters