Thanks for the explanation - I did pick up that if the pivot directly above the stylus, then it cannot be self aligning. They claim that the pivoted headshell deals with needle chatter.
It is important to note that in both of the above cases the "design" of the underhung arm had the ability to absorb the energy caused by mistracking.
If we accept that angular error causes mistracking, it seems entirely plausible that how the arm deals with and recovers from a less than ideal situation could play a large role in the sonic signature of the design.
This is of more concern to me - mistracking damages records. This would be a high price to deal with the vagaries of anti-skating, even though In my experience most folk apply too much anti-skate, resulting in offset cantilevers over time.
Most interestingly during an audio hiatus I ran a high compliance MM in a linear tracker for 10 years with the same stylus - cantilever was still dead straight despite the highish horizontal mass. Of course there are no skating forces with a linear tracker.
Is it possible to reverse the headshell 180 degrees with the RS and run a trailing pivoted headshell ?? Could be interesting.