As far as your tail wag goes....how are you setting the gain.....are you using the gear endpoints or gyro sense menu? Generally, if you get tail wag in HH mode, you need to turn your gain down. If using gear endpoints, a good starting point for the gain will be 32% (anything positive is HH, negative is rate). If using gyro sense menu a good starting point is 72% (anything above 50% is HH and below is rate).

If you haven't already, I HIGHLY recommend you go over to helifreak and watch the Finless Bob video on setting up the GY-401....he uses the 9650 in the vid as well.

Good luck,
Skarn