I suffered from angst about azimuth and as I was using a Graham tonearm it was very easy to change, however the results of using a mirror and my ears and a test record were contradictory. Being somewhat OCD by nature I ended up getting the Dr Feickert Adjust + software which, while providing hours of "fun" very reminiscent of the engineering labs at university, did sort out the problem once and for all - the stylus on the cartridge I was using was mounted about 1º off from square. I now use it whenever I mount up a cartridge with anything other than a spherical tip.
David Whistance
PS - Should say I also have a Tenuto which I like very much on my Garrard 401 - speed stability, which wasn't bad before has improved and I no longer need to use any damping rings.