@terry9 I have read your posts in the past and you show out as having a mind for the engineering side.
To get a idea of where my endeavours are going, the SP10 Thread on DIY Audio throughout the latter of last year and into this year covers a range of the platter designs to be used.
The designs for the bearing are coming from different places in Aus' and the UK, there is not as much work believed to be needed to create the measured run off's that are quite attractive.
I discovered the benefits of improving a generic type bearing design more that 20 years ago on a Garrard 401. Owned TT's since, that are in regular use, have all had a treatment in this area.
My interest in the Lenco GL 75 has enabled myself to meet quite a few who have done very successful work with this bearing type.
I am a vociferous advocate and encourager of carrying out this type of modification, meeting with a trusted support is the hurdle to be overcome.
My friend who has worked extensively on GL 75's, has gone to the extremes of having a Lenco Bearing Produced with a two part composite Spindle, Metal Spindle > Delrin Bushes in the New Machined bearing housing. The spindle to platter interface is using a material attached to the metal part of the spindle, where the material can be Natural, Thermoplastic, Metal or even a Composite.
When experiencing this in use as a Ebony Wood > Stacked Platter, the improvements was very very noticeable and quite outstanding as a functioning part when compared to other bearing modifications immediately available to try.
This is a Spindle Mod', I am in discussion about for the alternative bearing design referred to earlier, Panzerholz would be my wood of choice.
There is a more complicated bearing design in the making, I can't discuss it too much as it is not my work.
I have struggled to get a discussion going on a Air Bearing design. I have in my thoughts a design for one. I have to wait to see if it can be adopted into the design for this new complicated bearing design, seeing the dimensions of the New Bearing Housing and working with them, to offer the Air Bearing the optimised set up will be the challenge.