We're currently looking for a dog door so the boys can have free access to the backyard. What we have is a sliding glass door, so we're looking at the type that is built into a glass panel. Does anyone here have one of these? Also, how wide should the opening be? My husband went to Home Depot today and the one they had was ten inches. At the same time, the manufacturer advertises custom made. It sounds funny, but no one at the store was able to tell him if indeed the customer could give dimensions and the door would be made accordingly. Any help would be greatly appreciated!