Hey Lew,
This arm is a paradox. It clearly does not appear to have the same 'weighting' for TAE as a conventional pivoted tonearm. Mijo mentions above that there is skating in all non-linear trackers but I think it needs to be clear that the nature and magnitude of the skating on a traditional arm is much greater than that of its underhung brethren. I mentioned earlier in the thread that when I placed an underhung arm on a blank record surface it pretty much stayed where I put it with no anti-skate dialed in.
When we get to a situation like this where experience conflicts with traditional beliefs I always tend to side with the experience and then look for the unique details of the specific situation to try to better hone my views on the traditional. In an underhung arm the single null point can be manipulated by either changing the amount of the underhang OR changing the zenith. My gut feel is to set the zenith to keep any skating to a minimum then adjust the underhang to set the null.
dave