To see GSX at its full capabilities, an FSDT scenery might be best suited, since they are more carefully customized. I suggest JFK, for example, since it has different services available, like marshallers, docking systems, etc. Since JFK is also available in Trial, you wouldn't have any problem testing it with GSX.
An SDK is planned, this has been asked and answered several times, but we need the program to be more stabilized in features.
