markind,
Any REVO mixing in your DX6 radio should be turned off. Not sure if this is applicable to the DX6, just a heads up.

Spool her up and get her slightly light on the skids and watch to see if she holds true. If the tail spins radically to the right your gyro needs to be reversed. 50% gain in your tx is normal, I started @ 42% w/ my T-rex and ended up comfy w/ 51%. I left the manual gain setting untouched.

Make sure your switch for the HH mode is ON.

You're gonna love the HH gyro once you get it locked in.