I too added the default FSX GPS to the panel.cfg, but I aso changed either the position a particular 2D panel appears, or just changed its size.

I don't know really know how much changing the wing_incidence, htail_incidence, and aileron_incidence to "0" value in the Captain Sim 707 package will affect it. I don't have the bouncing issue, so the changes I make to the 707, are normally only in the [CameraDefinition.Xxx] entries, and nothing else.