Nandric,
I think a magnetic set-up could provide for variation of the force with respect to the radius of the LP, depending upon how it is implemented. So, since there are many tonearms that use magnetic methods, why is the Sony so much better?
To the OP, Since the skating force is varying constantly along the surface of the LP, is a moving target that you can never hit with confidence, there is no point in getting worked up over the exactitude of the anti-skate force.
Salectric, I have a Triplanar, and I have listened to it with no AS. In my system, I hear a pronounced and obvious distortion in the R channel especially. This is cured by re-application of a very small amount of AS. From this I concluded that the Triplanar, or my Triplanar, sounds best with a very small amount of AS. I know that Doug Deacon and some others also expounded upon the evils of the Triplanar AS device, that it introduced some spurious resonances, but I don't hear that problem, either, so long as all the attaching screws are tight as possible.