Any deviance from straight is ’oppositely’ reflected in a mirror, this makes it very easy to see and get azimuth straight
I use a 4" x 6" x 3mm mirror,
https://www.amazon.com/dp/B07T31MRZ9?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1

if you are a minimalist, this protractor is a mirror, same thickness as an LP. you need to make your own solution to measure overhang, and simply take it off the spindle, put it under the cartridge to set azimuth.
https://www.amazon.com/Turntable-Cartridge-Stylus-Alignment-Protractor/dp/B005KR15HU

my latest find, a 30x magnified mirror with led light to keep below the cartridge to see the underside of the stylus
https://www.amazon.com/dp/B0CLLZYBVK?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

I use this hudson hifi protractor, it has overhang measurement rings, and the other side is blank to watch and set anti-skate. I have a separage lp blank both sides for just anti-skate, will simply replace it after it get’s too scratched up from use.

and I needed some stylus cleaning fluid, it comes with a very nice wooden handled brush, tall bristles to clean the stylus
https://www.amazon.com/dp/B0CQC1TN25?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2

finally, not for azimuth precision, I use the mirror, but to check if the flat part of the headshell/cartridge is parallel when in the groove (arm height afjustment), these small bubble levels, you leave them on, pick 6,7,8,9mm size, kit od 5
small bubble levels
