Thanks for that link. It’s a nice summary of what has been audiophile doctrine since, I dunno, the days of Peter Aczel. Yes, the author didn’t mention zenith angle, but nonetheless, I’m impressed that he or she realized that it’s rake, not VTA, that is a significant alignment parameter; and did point out the importance of tonearm bearings, which can certainly be more important than even cartridge alignment in affecting the reproduction of sibilant content.
The sad thing is that it’s impossible to properly set any of these angles reliably, even with a protractor, without a microscopic analysis of your cartridge. Cantilever and stylus angles, even on four- and five-figure cartridges, rarely are correct, and sometimes are so far off that a cartridge cannot be aligned at all.
I’m not just giving a Wikipedia opinion here. Check out some of WAM Engineering’s tutorials (and Mikey Fremer’s old AnalogPlanet articles) for details, documentation, & photographs. Lots of well-documented information at https://www.wallyanalog.com/blog and WAM’s YouTube channel.
FWIW, I’d wrestled with my own sibilance issues for a long time, since moving from vintage tube gear to a modern solid-state setup, and only this year do I think that I’ve finally solved the problem.
As is often the case with persistent issues like this, there were multiple causes. My $2000 "silver-coated-copper-but-doesn’t-sound-like-silver" phono cables did -- sigh! -- sound like silver after all. My "class-D-but-doesn’t-sound-like-class-D" amp still suffered from some classic Class D anomalies. And my $800 MM "tracks-as-well-as-most-moving-coils" cartridge simply did not track transients as cleanly as a Hana Umami! In retrospect, none of this should have been a surprise, but it’s easy to be influenced by the opinions of colleagues and the claims of manufacturers. Sometimes, there’s no way around rolling up your sleeves and simply experimenting yourself.
I guess this kind of logical problem-solving process is one thing that makes this hobby so addictive. When you finally get everything right, it feels like you’ve really achieved something.