When you guys are balancing your wheels, I assume the radial hole set screw ring stays put for both the initial run in (thus dressing the wheel OD perfectly radial to the shaft center dictated by the ring/arbor) and then directly to the balancing bars for set screw adjustment?
I think @Dabbler's reply nails it.
But I share your concerns anyway. The hubs on all of mine are tight. But I don't think it hurts to be a bit anal about the positioning.
It turns out that there is more variability in the OD of the hub shoulder than I expected - especially between different hub manufacturers. So each balance ring should really be customized and mated to its own hub. The Precision Kinetics balance ring is designed to address that, but I'm not about to do what they did. Another plus for epoxy I guess.