>  Doesn't the DG's ball always indicate slip/yaw away from the direction of
> rotation?
>  So, step on the ball, we were taught, and it works, stopping the turn.

Not in an actual spin, where one wing is stalled, no.  If the instrument is
on the left side of the panel the ball will deflect to the left in a spin,
no matter which direction you are spinning.  If the instrument is on the
right the ball will always deflect to the right.

 

My training indicates you should use the turn needle and not the slip skid ball to determine direction of turn.

 

Jeff