VNS equatorial platform, Southern bearing question

[LondonNeil]

I'm trying to get my head around Southern bearings for eq platforms.  It seems a big advantage of vns designs is a point bearing for the South bearing and consequently a 3 point contact overall..  I can't understand how the design of the north bearing (VNS or CS) affects the southern, and hence can't see how the southern can be a point bearing unless it's the point of the cone, in which case the axis of rotation is unlikely to coincide with the CoG of the scope.  Am I missing something?