Thanks All,
Guess I didn't make it clear that my old Kadet Mark II trainer doesn't have any actual openings for windows. Much like the more modern LT 40 that RCKen described, the cockpit area is just balsa. Windows are simulated with covering of a different color. I today found some "Ultra Trim" in a silver color, small roll, that will probably work OK for my purposes. It's an Ultracote iron-on material.

Thanks for the help,

Frank