Hey,
well thats not that easy to answer !!
The ackerman effects more in the corner, not that extremely much in the first point of the corner. For the really first point of the corner i would say the front toe out and the car setup is more relevant. But in the corner the ackerman is the man.
To explain it simple, the more forward you are, the more aggresiv the car becomes in the corner, while you lose a little bit on exiting the corner !!?
So what you have to do is >>>> try it !
It depends also so much from your driving style and the complete car setup.
Try it, and do not forget to readjust the toe out inthe front after you changed the ackerman position !!! A common mistake wich will ruin the effect !!
regards
Alex