I have the Mint, the Geo disc, The Feickert and the paper ones from Vinyl Engine.
https://www.vinylengine.com/cartridge-alignment-protractors.shtml
The Mint is the most exacting for overhang if your Pivot to Spindle is spot on but useless for alignment if P2S is off even a little. The Geo disc is more prone to user error for me because 1) I may not be able to see the pivot point I need for a reference and 2) I can’t continuously focus down the alignment rail to the pivot without peering over and then through my specs. The Feickert is nicer with some arms than others because of the ease/work of pivot locating. The paper protractors work well if I’m careful about punching the spindle hole.
Two possible caveats are 1) is the stylus mounted to the cantilever exactly right and 2) is the stylus tip cut exactly right in relation to the shank. In other words, any protractor is only as good as the cartridge build and your eyes and your ears. Listening is the final step. If the protractor says it’s aligned right but it doesn’t sound good, or just ho-hum, I try again. And it always gets better. I find "Good enough" rarely is good enough in high end cartridges.
https://www.vinylengine.com/cartridge-alignment-protractors.shtml
The Mint is the most exacting for overhang if your Pivot to Spindle is spot on but useless for alignment if P2S is off even a little. The Geo disc is more prone to user error for me because 1) I may not be able to see the pivot point I need for a reference and 2) I can’t continuously focus down the alignment rail to the pivot without peering over and then through my specs. The Feickert is nicer with some arms than others because of the ease/work of pivot locating. The paper protractors work well if I’m careful about punching the spindle hole.
Two possible caveats are 1) is the stylus mounted to the cantilever exactly right and 2) is the stylus tip cut exactly right in relation to the shank. In other words, any protractor is only as good as the cartridge build and your eyes and your ears. Listening is the final step. If the protractor says it’s aligned right but it doesn’t sound good, or just ho-hum, I try again. And it always gets better. I find "Good enough" rarely is good enough in high end cartridges.