Azimuth 2020

It's interesting when one compares "industrial" cartridges with hand-made ones.  Generally speaking the industrial ones like Audio Technica, for example, will usually line up symmetrically very well and generally better than the hand-made ones.

With my AT Art-9 I always begin by making a horizontal line of the cartridge and its reflection on a disk to be parallel.  That's just the starting point. After that, it's all by ear, and only a minute adjustment is required, so no "terrible cant."

As i noted earlier, it's critical that you have an easy method of tiny arm adjustments for azimuth.  But that's not very common at all.

terry9, I had the exact same experience with my Koetsu Urushi.  After I first acquired it about 10 years ago, I adjusted azimuth using my Signet Cartridge Analyzer.  There I first noted that "equal" crosstalk and "least" crosstalk are two mutually exclusive goals, and to obtain equal crosstalk, L to R and R to L, the azimuth angle of the Koetsu was ridiculously biased to one side.  I actually listened to it that way for a bit, and the experience was not good.  Fearing that I had already damaged the stylus and maybe some LPs, I soon went back to near 90 degrees where I could obtain low values but not equal values.  Maybe not even the lowest possible values, but I decided it was better to settle for that, and the sound was improved as well.  The Koetsu is one of those hand made cartridges that can have been less than perfectly constructed.  I subsequently had similar experiences with a few other cartridges.  Then I read a white paper which made the argument in favor of proper seating of the stylus tip in the LP groove.  It makes sense to me.

I don't know for sure but from the tenor of other posts about the Fozgometer, I am guessing it may operate by equalizing crosstalk, R to L vs L to R.  That is not my cup of tea.

Peter Lederman is the last person I would take advice from. As lewm suggests it is a record wear issue not a crosstalk issue. Crosstalk goes to how well the cartridge was constructed. The the crosstalk is not at it's highest value with the stylus perfectly upright in the groove then toss it. It's junk.
Next. Springstein, I am not at all sure what you are talking about. The only really important factor in regards to the mirror used is it's thickness which should be about the same as a 150 gm record. Why? The vast majority of us have offset tonearms. Because of the offset as the arm goes up the stylus leans toward the spindle. Azimuth in offset tonearms is elevation sensitive. Those with tangential trackers can use a coke bottle if they want. As far as what side of the mirror is plated? It does not matter. As long as the stylus is at record level and the reflection is perfectly symmetrical you are in business. 
Some people try to just eyeball the stylus. Bad idea. The stylus has glue around it which is never even and it can fool you. The mirror greatly magnifies the error and allows you to focus on the very tip of the stylus.
You need good lighting! Try it and you'll see. Just grab one of your wife's compact cases. There is a mirror in the top. Also don't forget to defeat the anti skate or the arm will slide backwards!

Lewm, that is correct it is just measuring the amount of leakage across channels and it does allow you to optimize this. As you have noted the problem is this does not guarantee a perpendicular stylus and the thing cost what, $300? A pocket mirror guarantees a perpendicular stylus and costs maybe a buck fifty?

Peter Lederman is the last person I would take advice from

whoa!