Juice you never did say what variant of the Corsair you are modeling? Your Tamiya model is painted and appears to be an F4U-1D without bomb racks, it never had a window, so the model is wrong. The window was installed on all F4U-1's and some F4U-1A's. It was basically worthless so it was deleted. On the field if a Corsair needed a repaint or repair it was just painted over. No F4U-1D's had this window.

If you still want it just cut the plastic oversize as it is in the full scale picture. Recess the wood to the thickness of the clear plastic, and glue it down with RC56 glue. When you mask for paint mask the area of the plastic that you want to remain clear, as the full scale picture. Do this after glassing but before priming.