I use 1/4" C channel to hold in the glass or acrylic. Based on your pic, the challenge will be mounting the C channel to your control panel, it needs to match the angle of your monitor. Hopefully you can still remove the control panel because then you can make a bevel cut on the top side of the cp which will create a flat surface that should be made so that it's perpendicular to your monitor.
Hopefully what I said makes sense.