What I don't get about OL tonearms, is that the angle of the up/down ivot is perpendicular to the arm. Every other tonearm I've seen has the angle running perpendicular to the needle/cartridge mount (i.e. Rega, SME &c.).
Good observation. It was a design choice presumably driven by cost. Tooling is undoubtedly simplified by setting the bearings at a right angle to the armtube, rather than offset by 22-23 degrees.
There is a sonic penalty however: making the vertical pivot arc non-perpendicular to the cantilever results in an azimuth change whenever the arm rises or falls, as over a warp.
Of course OL arms don't have an azimuth adjustment either. Perhaps they're not much attuned to that parameter or its effects on sonics, though in fairness I think you have to climb fairly high on the cartridge and system resolution ladder before small azimuth inaccuracies become a major factor. Stable azimuth, even if slightly off as with an OL, usually sounds better to my ears than unstable azimuth, as is common with many unipivots. Every non-reference level tonearm contains compromises. The ones OL chose work quite well IME.
Perhaps the Shelters with eliptical as opposed to "fine line" tips are more tolerant of small VTA and azimuth errors.
Very true, IME.
