Ok.. I'm trying to set up the new HD DVR receiver I received in the mail yesterday... to replace the current HD DVR I have. this may be a stupid quesiton, but during the set up it ask what kind of dish do I have? Well, there are like 18 choices!! Looking at my dish, it's not round, oval, 3 LNB's. The choices have for example: 3-LNB (18"x20") & 95degrees, or the same but 72.5 degrees, Slimline 3, Slimline 5, 3-LNB (18"x20"), 3 LNB & 72.5degrees and 95 degrees. How do I know which one to select?