Violent tail wag "THROTTLE CUT"

[Extensa]

I started up my 600 nitro today it spun up well in normal mode then I put it to mid stick and flipped adl up revs went up like it should but the tail went side to side by a foot which I flipped the throttle cut straight away before it crashed. I'm using a 3gx, Futaba R2008SB receiver and Futaba T8J transmitter on a align trex 600 nitro limited edition heli any one know what needs to be changed? Thanks, Mike.

[Varelco]

Sounds like the tail gain is too high. My 550 wags until its airborne because the tail fin gets stuck in the ground.

[Extensa]

I have it set at 60% what percentage would u recommend?