I have measured my steering shaft & steering column top & bottom diameters as best I can with my Aldi Calipers they come out as follows.
Bottom bearings are 50.00 mm OD, steering shaft diameter is 26.7? mm. ( not sure until I remove the bottom race if has a wider shoulder at the bottom where the race seats)
Top bearings are 48.50 mm OD, 26.00 mm ID.
As best as I can measure the original bottom ball bearing has a thickness of 13.50 mm.
This leads me to thinking that the bottom spacer needs to be the difference between the taper & roller bearing thickness plus any washer (if there is such a thing) that sits between the normal lower bearing race & the dust seal.
Any comments on my calcuations welcome please,