Dear @fusian : Around 90% of tonearm manufacturers used and use one of the 3 best knowed alignments: Löfgren A or B and Stevenson.
Those same tonearm manufacturers choose between different but " standard " tonearm efective lengths: 9", 10", 10.5", 11" and 12".
So run 5 times the VE calculator and you will know how measures the 90% of audiophiles tonearms. That's it.
R.