I'm not sure how useful this will be, but here's the improved version of my original alignment calculator, with enough bells and whistles that it's replaced both the alignment calculator and the alignment comparator, and gained the pro tag (!)Tonearm Alignment Calculator Pro
Basic functionality is essentially as before - enter either a pivot to spindle or effective length value, hit calculate and the script will return Baerwald (Lofgren A), Lofgren B and Stevenson geometries for that arm length, along with a plot of tracing distortion. You can also click on the null points of arms in the tonearm database to fill in the form automagically and compare the manufacturers alignment with optimised geometries.
Notable additions to the new calculator include figures for maximum tracing error (in degrees), custom name/length/overhang/offset angle for all plots (enabling comparisons of up to 4 tonearms of different design), presets for inner and outer groove radii and a plot of tracing error (this is the basic angular error data used to calculate the distortion plot).
Error handling has hopefully been much improved on the previous calculator, but the comprehensive rewrite may have introduced new bugs.
If you spot any bugs or layout issues please post here with details, thanks