Firstly, it would help knowing what Table-Arm, and what geometry is suiatble before making any solid recommendations to you.
Most Japanese vintage Tables will more than likely be better suited with Stevenson Null Geometry. Although some do like, and use Baerwald with Table like the Technics 12XX models.
Ifm you should find your TableArm will be suitable with Baerwald, there are numerous, cheaper options, suuch as a going to vinylengine.com, and downloading free protractors, and printing some up. Just make sure you double check proper scale size when printing to paper
Then there's Protractors like the Mobile Fidelity Geodisc (about $40), the Turntable Basics Mirror which is very good (about $24 shipped), and there are others like the Ken Willis Arc Protractor ($50 for a 3-Null, 2-Point Geometry Arc Protractor, Baerwald, Stevenson-Loefgren) The MintLP Protractor is another at $90, but is from overseas. Said to be a very good Arc Protractor as well.
With Arc protractors, versus Sight Line Type, like the Geodisc, or Turntable Basics Models, you will need to know the exact Spindle-Pivot distance specification of your Tonearm, and you should confirm this exact required distance by actual accurate measurement to be positively sure before ordering a specific Arc Protractor. I hope this helps you. Mark
