Dear don_c55: You have to think that in any tonearm alignment set up choice the distortion levels change ( up and down against where null points are. ) at each recorded groove or minimum playback tonearm movement and no one can detect those so small changing distortion levels.
The people that like to change null points or pivot to spindle tonearm distance can´t detect those distortion levels.
Some people say that with the new tonearm set up things sounds better and this " fact " cab be for two mainly reasons:
that the first set up was non accurate as the new set up or that even that both set up were accurate the person wants to hear the improvement because he think that with the new set up distortions levels gone down but this " gone down " is so tiny/insignificant that in reality can’t be detected!
"""" When you adopt a different alignment you're also changing effective length and offset angle. """"
This kind of sentences speaks of that audiophile mediocrity/low knowledge level where we " audiophiles " are " swiming " through.
You posted something critical: accuracy, and this is the name of the game with overall tonearm/set up. Anything else is only " imagination " not facts.
Regards and enjoy the music,
R.