what you need are the ANSWERS, distance numbers, for
a. install tonearm, centerline distance: spindle to pivot.
installed: CHECK IT IS CORRECT when you buy a Turntable. Something could move during transit, it may not be properly tight, or was done imprecisely, rare, but check it.
install: draw an arc, and find a location on the arc that keeps the rest of the tonearm within the dust cover when in place.
b. overhang distance, spindle to stylus tip, MOVE CARTRIDGE forward or back in the headshell, set overhang prior to ’c’.
c. two null point measurements, these vary relative to specific arm geometry. ALIGN CARTRIDGE’s CENTERLINE, find the best ’straight to the lines’ compromise for two arm specific null point locations.
Hudson Hifi Alignment Disc, Other Side Blank
has a grid of lines to use once you have the answers for ANY arm.
Use other blank side to set anti-skate last, see the arm move in/out/float in place as you make adjustment while manually spinning.
excerpt
The three advertized alignments and their null points are:
Baerwald 66 and 120.9
Loefgren 70.3 and 116.6
Stevenson 60.325 and 117.42