Tonearm Geometry and Setup

I thought that these were the product of the width of the record, which is a constant, the length of the tone arm, which varies, and the chosen formula [Loftgren etc] for producing the least distortion. This would appear to offer zero degrees of freedom so I must not have understood the question.

Stanwal, rather than not understanding the question, I think perhaps you answered it. The zero points are, as I understand it, calculated as you say -- so we are only free to "pick" a zero point to the extent we are "free" to pick one of the several formulas intended to identify the zero points leading to least distortion. True?

Dear Rdavwhitaker, true. No the question is, what are the best points and what does mean "least distortion"..... least distortion where on the records radius .... the groove is not homogenous, as the radius is decreasing ever more with lesser distance to the label and thus the situation for the stereo stylus is getting more and more "unbalanced.
Cheers,
D.

I am of course not (pre)supposed to answer my own question
but considering Stanwals comment I need to put my question more clearly. The context is this: 'we', or at least I, got the impression that I can choose the 'zero points' depending on which part of the LP I want the least distortion. Baerwald is about the best solution for the whole record radius (aka 'the average') while the other provide better solution for specific part(s) of the record. Ie Stanwals 'least destortion' in general will not
do. This thread as well as the question of 'choice' is caused by some remarks by Dertonarm in the 'Copernican thread'.

Regards,

Dear Nandric, "we" (... we, the people ...) do indeed have a choice which of several options we do choose.
It does depend on personal preferences, stereo or mono, vintage of the majority of the records one owns/plays ( how close cut to inner label ), effective length of tonearm and expectation in sound reproduction/ability of a given audio set-up to recreate soundstage dimensions and acoustical positioning.
Most will fare well with Baerwald/Loefgren A IEC, owners of mostly modern pressings with large wax will do great with Loefgren B IEC, collectors of early vintage stereo records of the 1950ies to mid 1960ies will prefer Baerwald DIN or UNI DIN.
There is no absolute - and there is NO mathematical "best".
It is - as long as this was about mono reproduction only ( and mono only it was when Baerwald / Loefgren A was postulated ) and when one assumes that the music engraved is VERY homogenous without huge climax' towards the end of a piece/movement.
But since music is anything but homogenous in volume or structure nor are all records cut following IEC, we have do address our needs individually.
Cheers,
D.