One big issue is picking the right focal length and field of view. A lens that has an adequate field of view will probably show the glider as a tiny little speck. A lens that shows the glider at a reasonable size will probably have a narrow field of view. And of course, where the camera is pointed becomes an issue that cannot be resolved in flight. Screen brightness and vibration is the next thing to worry about.

All of these factors can be resolved, but there will probably be some experimentation needed, along with trying several different components. Good luck, and please report back with your results, both pro and con.

Mirrors are cheap, simple and reliable. Placement is a matter of preference.. I have seen tiny mirrors on the struts (probably useless), medium size on either side of the canopy frame (better) and one large mirror inside the cockpit high and as far forward as possible to keep it out of the normal forward line of sight and above the place your head would go in a rapid deceleration.