Well, I bought some 66s on my way home to swap the hangers onto the Low baseplates, went to mount the last wheel, and the axle is defective; too girthy for the bearings.
After looking at the way the hanger sits on the Low bottom bushing, I was all excited to tinker with the taller Ace bushings to see how these can be customized. Will report back once I get this warranty claim sorted.