I have a rectangular/almost square kitchen window in which rests an air conditioner. I have installed central aire and would like to remove the air conditioner. Would it be advisable to just put a piece of glass cut to size towards the exterior portion of the window frame or should I get two pieces of glass and caulk one towards the inside and the other calked towards the outside with the gap in between? The window is an unusual shape, and I would otherwise have to have a custom window made. Thanks for your help!