I saw this pic in another thread

This is how I want to mount smoked plexi to my cab. I do not plan to use a bezel.
I am doing the screwing together tomorrow and laying the 1st coat of paint on sunday, so my question is HOW IN THE HELL DO I ATTACH THE PLEXI AND KEEP IT IN PLACE? I cant find this info ANYWHERE! Do I use a strip of MDF behind and screw it in place or what?
I know some people are using the control panel to hold it in, but my cab uses an x arcade (I know I know!) which slots into a cutout, I doubt it will have the weight to hold a sheet of glass in place.