You say it goes one way then the other etc..overcompensating is whats happening here...get someone to check your radio(if your not familiar with it yourself) and turn down the rates of your tail fore and aft cyclics to about 50% of what they could be and lash a load of exponential on the same sticks(you dont need much servo travel when your only hovering)...this will soften things out for you and the model will be more tolerant of sloppy sticks.