Zenith Angle Correction: The Final Set-up Frontier!
Wallytools is working on a multi-angled zenith angle gauge that will allow you to accurately set zenith angle for your cartridge based upon the degree to which the stylus is "off". All of this is currently "in the works". The inspection cost alone will not be inexpensive and certainly if you're spending $500 or so on a cartridge such a service ...