... the Feickert protractor is very good specifically with P2S distances, not so good with cart alignment, the Smartractor although more expensive allows you to adjust long tonearms and the cartridge with better precision
I have aligned "12 inch tonearm with Dr. Feickert, absolutely no problem with that.
Some people are referring to an old version of Dr. Feickert, but it was upgraded with the new version many years ago, it's precision protractor.
If you vision is not good it's the only "problem" with Dr. Feickert protractor.
I often see people overestimate the importance of alignment when they want to align their cartridge with micron accuracy that your ears can't detect anyway!