@ossicle2brain You have pointed out the points I made a concern for myself to attempt to improve upon many years ago.
My journey took me to the point that I was having Platter Spindle Bearing Interfaces optimised using the original housing to undergo modification.
That lead on to the complete Bearing Housing being swapped out for a new design one on a certain Brand of TT.
I have more recently reverted back to having other TT's have their original Bearing Housing modified, but there are now new ideas evolving that will mean new bearing housings are to be produced for my 'go to' TT.
The efforts have certainly improved centricity of the Spindle Rotations and when the parts are bespoke produced for each Housing Spindle, the run off measurements are much improved over the OEM.
Unfortunately if very low microns being recorded are to be goal as a measurement, then the original bearing designs are not able to cut it, a rethink and substantial materials are required to produce the redesign.
At present there is a lot on offer to minimise the impact of non-centricity of the Album, and reduce the fluctuations that can be detected in the speed.
An off board - standalone strobe will quickly show speed fluctuations due to eccentric rotations.
Hydrodynamic Lubrication is a almost impossible condition to maintain within the bearing housing when working with a typical journal bearing design. It is strongly suggested metal/metal contact will occur, this occurrence equates to noise and over time wear of a sacrificial parts metal, resulting in abrasive dust as an interface.
Removing metal/metal contact, as a result of exchanging parts, has a major improvement on the noise produced at the time of Spindle and Sacrificial parts coming into contact, the method certainly removes concerns for abrasive dust as well.