I finally tuned my quad with the apm2.6 board with version 3.1.2
But when I fly in loiter mode my quad tends to do the toilet bowl dance. This I because the magnetic north changes because of the magnetic interference caused by all the electronics onboard.
The solution to this is to do compassmot stated in the 3dr website. What this does is tells the compass the correct north by not registering the magnetic interference.
now one more problem has come up.
after the compassmot my interference was 5%, but now my motors are not spinning fast enough to take off even on highest throttle.