Forget about parallel or whatever setting "LOOKS" right,and start to listen for what sounds like the most accurate timbral definition.This should take a few listening sessions with a wide variety of material to play.Right on! Timbral presentation of familiar (acoustic) instruments is exactly what this is about. The mix of frequencies that constitute the sound of any instrument occur in a certain temporal order. Changing SRA changes the timing of when the stylus engages each frequency cut in the groove, which affects their temporal inter-relationships. The right-sounding SRA falls within a very tiny range of arm heights, but when you find it the sound of the instruments becomes more correct or "real" and every instrument has tighter, stronger micro-dynamics.
Also,and importantly,try to have some GOLDEN EARED audio pals over while you play with the vta.Experimentation is a "GOOD" thing here,and you will learn about your set-up.Indeed. Two (or more) sets of ears are orders of magnitude better than one, as are two or more brains for problem solving.
Last night I spun the Classic reissue of Munch/BSO/Tchaikovsky, 'Romeo and Juliet' + Strauss, 'Till Eulenspiegel'. Okay, okay, I know it's fluff - but it's FUN fluff.
Curiously, the yellow sticky with arm height settings indicated the same number for Airy 2, Airy 3 and UNIverse. This seemed odd. The Airy 3 usually wanted the arm about 8/100ths of a turn higher than Airy 2, and the UNIverse typically likes it about 2/100ths or so below that. Nevertheless, I set it where the sticky said and spun it up. I wasn't listening critically and didn't pay much attention after that.
Halfway through side one Paul walked in from the den (two rooms away) and asked, "Did you adjust the arm height? It isn't right." Freakin' golden ears! He reset it and we updated the stupid yellow sticky. It was off by 5/100 of a mm. Oy!
Moral: you don't need to be in the sweet spot to hear SRA changes, you may not even need to be in the same room! Say, do CD's need this level of madness?