I've been asked to make some Gothic window panes for a large cupola and I am wondering if extira would be a good product to use. Basically it will be a carved MDF cabinet door, 24" wide X 36" tall. I plan to rout the back out for one large piece of glass rather than true divided lite. They will get plenty of sun and weather exposure. The will not bare any weight. Would this hold up with a good paint job?