I'm a future Dish customer and I've been lurking in the background absorbing all the answers to my questions for several weeks. About roof mounting the dish though. I'm very concerned about leaks. I see a lot of them mounted on roofs so I guess that is a method to use if there is no clear line of sight but I do see some that do not have a line of sight problem. If the installer suggests a roof mount, how much can I or should I insist on a wall or facia mount before he walks off the job?