My Kleos/SME 309 did not track well with Brakemeier's Uni alignment so I used the cheapo SME paper guide to put it back to whatever the SME standard is.
SME depends on the cartridge manufacturer to conform to industry standards set long ago. Unfortunately cantilever length varies slightly from manufacturer to manufacturer and even same manufacturer between quality levels.
The MINT protractor is custom built and if you supply a photo of your cartridge showing cantilever and diamond against a clear ruler (in MM) they will build the perfect protractor.
SME achieves overhang by varying spindle to mount distance via the geared mount assembly. When you move that distance to accommodate the stylus the geometry is no longer correct.
The MINT protractor is marked for exact turntable (spindle diameter) plus tonearm brand AND cartridge brand. I think it's the most accurate with Wally and UNI close behind.
The good news is the MINT is cheap, about $100.00.