...dead on azimuth is where the phase is aligned, not gain. the image snaps in based on phase being equal in each channel.Now that you mention it Mike, this makes more sense than merely minimizing crosstalk.
Reducing stereo crosstalk certainly helps a binaural listener estimate the size and direction of a mock-single sound source coming from two speakers. But the image will only "snap into focus" when phases are precisely in synch AT THE LISTENING POSITION.
Given the effects of room interactions, which Fozgometer, Wally and oscilloscopes cannot hear, one could argue that final adjustment by listening is THE most accurate method for musical listening purposes.
For me as for you, setting azimuth is a simple, two-stage process:
1. make the stylus look vertical by eye (resting on a mirror helps)
2. fine tune until the image snaps in (this can be done listening to music if you don't enjoy test tones)
Measuring devices just over-complicate this straightforward, though vital, adjustment.
Agree the Talea's on-the-fly azimuth function makes it very easy. I've played with it for visual azimuth but didn't have time to fine tune aurally during my too-brief audition of that exceptional tonearm.