First target is an accurate cartridge/tonearm geometry alignment choosed: accurated P2S distance, accuarted overhang and accurated offset angle.
We can be " anal " to set up the VTA/SRA parameter or all the other ones named here but even that we made it with a true reference as live MUSIC ( not Tidal or LPs. ) things are so imperfect in LPs manufacture that with the same LP things are " perfect " in side 1 but for different reasons the quality level performance in the side 2 is well different ! ! ? ?
In the other side each time we make changes in VTA/SRA the AZ changed too. Any one can use a tiny level at the headshell and make a significant change on VTA up and down and you will see that AZ always change. With some parameters exist an intrinsecal relationship that make imposible that each one of them stays " perfect " and no matter what the LP/analog imperfections will make that our hard and time consuming work falls down.
As better the audio system resolution as wider range margin/limit we have for the VTA/SRA set up, the window is a little wider ( quality really acceptable. Obviously is one and only one point where belongs " perfect " VTA/SRA. ) and that permits that even with all LP imperfections we can stay nearer to the VTA/SRA accurate target.
Those LP/analog imperfections impedes that all of us can have precise/no-compromise rules about because that does not exist and additional to that the tracking error in pivoted tonearms at each single groove makes things more complicated.
Again, what we want to do must has a reference and mine always is live MUSIC at nera field position not: " I like it that way " with no true/real coherent reference at all.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.