Taking a machining class and have a few projects that involve manual milling at 45 degree angles. Basically a cube that I need to locate center on while mounted in a vise with V blocks so the block is 45 degrees to the table. Was told to just use the center finder against the edges even though the travel of the table is not perpendicular to the face that the center finder will be hitting. Seems like the angle might make the tip move sooner in one direction than the other.

I tried it and used both slopes to try to see the difference. Seemed pretty accurate. Is this generally accepted to locate? Is there some rule of thumb to the amount of angle where it gets unacceptable?