1) My only suggestion would be fairly simplistic: experiment with the orientation and placement of the antenna.

2) There is a bug in the speaker setup that prevents you from disabling both the center and the surrounds. If you're only running two speakers, you can pretty well treat it like a normal stereo setup and skip auto-setup entirely - the channel calibration really comes into play when you start trying to get equal sound levels from different speaker models at varying distances from the listener, which is why channel calibration was never really an issue in stereo systems.