Dr. Feickert Protractor

What will Dr. Feickert's protractor do that the paper alignment protractor that came with the turntable can't do? 

Proper analog set up is something you want to get right. In my experience even the slightest variation from the standard that this tool allows you to hone in on, has a negative effect on sound quality. The Dr's tool just allows you to get "perfection" easier than any of the others I've used. It is expensive though.
The current edition offers 3 different scales to choose from. Lofgren, Baerwald and Stevenson the latter is really good for Rega tables. The beauty of the tool is it's ability to triangulate the three points of spindle, arm pivot and stylus overhang. I have used mine to set a Kleos on my RP10 and have found it very beneficial in set up. I used to use the MO-Fi disc and then bought the Avid plate. But the protractor provides a more precise method of measuring arm pivot to stylus. 
Also besides these features, the grid aids in getting the cartridge aligned at the proper angle. In truth it is a tool that I may only use once or twice again in life, but wouldn't want to set up a cartridge without it. 
That said the Avid plate actually had me very close and if you don't want to invest 250.00 the 45.00 for the Avid does a nice job as well. 

I really could not do what I do without it. for example, currently messing around with  different arm board materials, different thicknesses, different shapes. for me, it helps speed  things along when the "madness" takes over..... of course, if I did not have it, I may leave well enough alone...