Phono Protractor. Recommendations?


After purchasing a new Cartridge recently, I'd like to purchase a good protractor.  There are so many available, each claiming to be the one to have, I'm confused.  
What do you recommend?
louisl

@larryi 

I have made up some small wedges out of cedar wood. Works a charm, and they are very soft, so no scratching to plinth/platter, and easy to make with an Exacto knife, or box cutter.

Something I've never understood: If you are lined up perfectly at point A, how can you not be also lined up perfectly at point B? Then what do you do? compromise between the two?
Point B is just to verify that point A is correct. if point A is perfectly lined up then point B will be perfectly lined up. if point A is slightly off then point B will be slightly off.