Setting Azimuth

I've attempted to set/fine tune the azimuth on a Graham 2.2 using the KAB device made to test azimuth (and a mono LP). I have not been able to achieve complete silence -- which is my understanding of what I am aiming for with the KAB device. No matter how much I tweaked the azimuth adjustment on the arm, I always had some sound coming through. The volume seemed to vary with location on the LP -- i.e. between the outer tracks and the inner tracks. I then swithched to using a headshell level -- got the arm level -- and still heard sound through the KAB. I have the anti-skating force set as low as the arm allows. My questions: (1) is what I'm experiencing a result of the anti-skating setting? (2) what exactly am I supposed to hear when setting azimuth using a channel cancelling device like the KAB (3) what else might I being doing wrong. Thanks for your help.