His post says that the PG03 is a HH only gyro ... it doesn't have a non HH mode ... so you can't switch from one mode to another.

I would suggest ...

1) Disconnect the gyro from the RX
2) Plug the t/r servo directly to the RX (where the gyro was plugged in at).
3) Power up TX and heli (less motor connections)
4) Verify TX stick to servo response direction. Reverse channel as required.
5) Mechanically trim/center your t/r system ... ie TX rudder stick and trim centered, t/r linkage intersecting servo arm squarely, t/r linkage length adjusted to set slider in center of travel range.
6) Power Off heli. Disconnect servo from RX and plug into gyro. Plug gyro into RX.
7) Power up heli (less motor).
8) Set limits on gyro so that there is no binding at limits.
9) Power Off heli. Connect motor. Power on heli. Test fly ... set gain as required.