You can do it, but it plays hell on planer knives.
I would router a Rabbet 1/8" deep around the bottom of the CP. This will allow the bulk of the material to be 3/4", but the edge you see with T-molding on it will look like it is 5/8" material with 1/8" plexi. Knievel uses this technique all the time on his builds. You might peruse a few of his threads for details.