For one thing, when your heli is still on the ground while you are spooling up and getting ready for takeoff, it is normal for the helicopter to change position on its axis (like yaw left or right on its own). It is also normal for the tail motor to kick on kinda later than the main rotor. It is also normal for the tail rotor to stop or slow down dramatically when you apply left rudder. And when you apply right rudder the tail motor should spin fast.

I think you will find that once you get your helicopter off the ground about a foot or two, it will clear its own downward thrust and turbulence and the tail should hold. When its on the ground you get vibrations thru the landing struts which may affect the gyro, and the gyro tells the tail what to do. Also when the heli is on the ground, the ground is counteracting the torque of the main blades somewhat and thats why the tail motor doesnt kick on. No forces to counter at that point.

If your helicopter changes position on the ground while you are spooling it up, then hold it at a throttle just before where it would lift off, physically walk around the helicopter until YOU are behind the tail, and then throttle up higher to lift off.

hope this helps.