Most cartridges will exhibit at least some zenith error. Parenthetically, for those who don't already know, zenith for us audiophiles refers to the angle that the stylus contact patches for left and right channel information, respectively, make with the groove wall. Someone else quoted the industry tolerance for a +/-5 degree error, which is huge. Because of zenith error, any subsequent effort to "zero in" on the alignment of an overhung, pivoted tonearm is folly. You won't get the null points where you think they are, if indeed you get any null points at all on the playable surface of the LP. So, for me, once you've set overhang and VTA, the most important thing is to correct for the inherent zenith error built into the cartridge. And yet, only Wally has marketed a tool to correct it, so far as I know, and I have heard that the tool is difficult to use and/or may require sending the cartridge to Wally. But if you are finicky about alignment, you gotta face the music.