Basically, when you bank the aircraft, inertia will keep it from following a true circular path, it has a tendency to 'skid'.
The rudder will be applied in the direction of the turn to counteract the 'skid'.
The only time opposite rudder is used is when a slip is wanted. The side slip is used to either loose altitude
without increasing airspeed or in a crosswind landing to point the nose down the centerline while banking into wind to
counteract drift.
I have never heard of turning using opposite rudder and in fact that would be counterproductive.
And the practise of adjusting CofG to stop the nose from dropping during a turn is
in my oppinion, a dangerous act that could put the CofG beyond limits. The nose will
drop as stated in an earlier post, due to the physics how lift is developed and how the
lift vectors are tilted during a bank. It has nothing to do with the CofG.
Dan