Raul,
I see your point about the three parameters all being minutely affected when one changes his VTA setting. I also agree that the settings Doug wrote down for his VTA for each of those 1,000 LPs is useful information and saves him time when he plays one of those LPs. Those settings will be different with a different cartridge and probably with a different arm, especially one that does not have the same calibration or markings on it for repeatability. He will contend with that how he will.
However, I was at the listening session last weekend when we auditioned the Ortofon A90 and Doug adjusted VTA/SRA for each LP. I know what I heard and the results were much better after Doug did his adjustments. I learned a lot from his expertise. I don't really care if the improvements were in fact SRA related, overhang related or spindle distance related. That is for arm designers to worry about IMHO. His adjustments were easy to make given his experience, ears and the fantastic arm. And they were well worth the effort on a cartridge like the A90. We all make trade offs in this analog hobby, I agree with you. I don't plan go to the effort of changing cartridge alignment for each LP. The "effect" of changing the VTA/SRA setting is enough for me once a good average alignment is achieved and if the arm is capable of easy VTA adjustments.
I see your point about the three parameters all being minutely affected when one changes his VTA setting. I also agree that the settings Doug wrote down for his VTA for each of those 1,000 LPs is useful information and saves him time when he plays one of those LPs. Those settings will be different with a different cartridge and probably with a different arm, especially one that does not have the same calibration or markings on it for repeatability. He will contend with that how he will.
However, I was at the listening session last weekend when we auditioned the Ortofon A90 and Doug adjusted VTA/SRA for each LP. I know what I heard and the results were much better after Doug did his adjustments. I learned a lot from his expertise. I don't really care if the improvements were in fact SRA related, overhang related or spindle distance related. That is for arm designers to worry about IMHO. His adjustments were easy to make given his experience, ears and the fantastic arm. And they were well worth the effort on a cartridge like the A90. We all make trade offs in this analog hobby, I agree with you. I don't plan go to the effort of changing cartridge alignment for each LP. The "effect" of changing the VTA/SRA setting is enough for me once a good average alignment is achieved and if the arm is capable of easy VTA adjustments.