I like a flat top so I can put these small bubble levels on the headshell. I just found two arms that the headshell were not perfectly parallel to the arm, it’s the cartridge body, thus the headshell you want level
https://www.amazon.com/dp/B07NRG8HX6?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2

I use 10mm double faced dots to adhere them (removable)

https://www.amazon.com/dp/B0DKJJV58Q
I use this mirror on the platter (same thickness as an LP, if the stylus/cantilever is not straight, it is reflected ’opposite’, thus it is easy to get it straight.
https://www.amazon.com/dp/B07T31MRZ9?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2


