Good stuff, Thomas_A.
If the platter weight is uniform, say made from a solid cylinder, then I =(m*r^2)/2. If the weight is entirely around the rim then I = (m*r^2), i.e a factor of 2 bigger. So perhaps a reasonable approach to estimate moment of inertia with the Linn Axis platter is to estimate how much weight is on the rim and choose a factor between those limits, in proportion ? And hopefully someone out there knows how much a Linn Axis platter actually weighs ? Just that it is necessary to know, unfortunately.
Those absolute friction numbers you measure (0.005N - 0.0075N are lower than those I measured (0.0089N - 0.0093N). Your figures equate to c 0.5gf - 0.75gf for a VTF of 1.4gf, whereas my figures equate to c 0.9gf for VTF = 2.0gf . However, as you say, the friction co-efficients seem about the same, though yours is probably a bit lower. The stylus profiles are very different, of course. But much depends on being confident of a true estimate of the moment of inertia of the Linn Axis platter. My platter is a solid uniform cylinder, so moment of inertia is pretty well determined.
Still, accords with Yosh's range of coefficients though, which says something for the method.
Must get a better bearing !!!