You are making too much work for yourself. There are mirrored alignment tools that are punched to fit your spindle and have a straight line already inscribed.
These are non magnetic, reflective to aid in evaluation of azimuth and designed with beveled edges and ultra smooth surfaces to minimize trauma on the stylus.
Place the mirrored tool on the spindle and make it as close to 3:00 O'clock as you can. Push the arm along the line to determine if the stylus runs in front of the line at either the outer or inner edge of the LP.
Slightly rotate the platter to bring the line to match the stylus. If the stylus is too far behind the line, mount it further out on the head shell. For the other direction, do the reverse.
It is not possible for you to get this wrong as long as your cartridges stylus traces exactly along the line from outer to inner most positions of the LP.
The tool I use is the Ortofon RC 018. A quick search with Google turned up this page where one is for sale:
http://www.sunflower.com/~jlhamm/equipmen.htmI think I paid $15.00 or so for mine at a CES a few years ago. If this one is not available, other brands are probably just as good.
Sorry about your Benz, that is a great cartridge. Hope your able to get the tunes flowing again soon. It will make everything all right.