I agree, Doug. It's not that one protractor is superior to another. All should work very well if they are used properly. But one could work better for someone versus another style protractor, depending simply on which may seem to be more user friendly. However, getting back to original question, the placement of the tonearm is still very critical to get right no matter what protractor one uses.
I guess I don't in either Swampwalker's or Doug's "eyesight camp". My eyes have gotten bad in both near and far sight over the years. Good thing there are also great optical tools available as well as great protractors! It really is an excellent point. I think it is easier for me to see of the stylus is on or off the arc. Once I have that, squaring up to a single point is simple. As long as I don't move the cartridge screws too much forward or back, things are good. But re-checking the alignment with the arc after squaring the cantilever up is still a good idea. Just as with the two point protractor, it is an iterative process.
