I adjust my CB750 according to the marks. At idle and full advance not before 2500rpm.
I had to cut both adv springs 1/2 wound on both my CB750's to make that to work.
Advancer has a play, set it to max counterclockwise and marks will be true.
I do not care of any degrees, only when timing a cam, not stock one.
I'm sure that wrong information that more advance will work better is spread worldwide
I saw on Dyno that only a few degrees more advance than the marks lost HP. That on my modified K6.