what is the purpose vta adjustment? some say it is to duplicate the angle of the cutting head. If you accomplish that you have got it right. other's adjust vta for the "best sound".Your two "alternatives" do not represent different purposes. They represent different techniques for achieving the same purpose.
The purpose of our hobby for me is maximising musical enjoyment in my home. I set arm height for best sound, since that maximizes enjoyment, but isn't it likely that I'm also matching stylus angles, within the limits of my hearing of course?
I listen for and hear certain specific things while adjusting arm height, so it's reasonable to think there's a consistent mechanical explanation. (That hypothesis is the topic of this thread.) My current unproven belief, until a better explanation comes along, is simply that I'm using "best sound" as a proxy for matching playback stylus angle to cutting stylus angle.
Whether I'm matching as well as one could with a scope or other measuring device is of little practical significance. Optimum arm height varies from record to record. Having to drag out a scope to calculate arm height for every record would be wildly impractical for home listening. I can adjust arm height to my satisfaction while listening to and enjoying the music. As Rushton said, using a scope to set azimuth is preferable. This is because, unlike arm height, azimuth does not change from record to record. Use the scope once and forget it until you change cartridge or arm.
If I were playing LPs for archival or commercial transcription to digital I would take the time to get SRA technically "perfect". But for home listening that seems over the top to me.

