Best Alignment Protractor?

Mint Best Tractor for me.  Perfect and the most accurate on the market

Original Dennison for me unless I am setting up an SME where I use theirs.

I’ve also used both versions of the Feickert which are fine, I just prefer simplicity.

I use a modified Mobil Fidelity Sound Lab's Disc.  I added an overhead pin to center on the spindle, dead center.  I may adjust the cartridge, by moving it ever so slightly forward or back to suite me.