[Markd51]

I have the MintLP, have to say it is probably one of the best, but as the OP, and others recognize, it is tonearm dependent.

As for sight line Protractors, I have 2 on hand, bought previous to the MintLP, the Geodisc, and the Mirror Protractor sold by Turntable Basics I believe it was.

The one from Turntable Basics was only about a $24 Tractor, and IMO is as good, if not slightly better than the Geodisc. I liked the mirror feature, and if memory serves me correctly, the TB Tractor has two null grids for another check of proper Zenith Alignment, whereas the Geodisc only has one null grid.

Both are susceptible to sighting errors, dependent upon how good your alignment skills are, in determining center of Arm Pivot. And either can be enhanced and further 'accurized" by the use of a simple piece of thread to extend the sight line to the Arm Pivot.
Hope this helps.

AFAIK, all I mention use Baerwald Geometry. Not sure if the Regas go by such?
Mark