Sounds like you guys are impressed with the bell hiller head. I made a list of stuff for the guys at my shop to order and the hiller head was on there, so we'll see. However I'm still going for my upcoming T-Rex 450XL because of the driven tail, while fixed pitch tails are simple and nice, they do NOT get the job done very well in my opinion and they are not accurate enough. I doubt you could use a heading hold gyro with a fixed pitch tail and get much improvement over a rate gyro.