[quote name='kleraudio']..behind you or on the side?/QUOTE]
To the side.
As for the distance...IIRC it's "distant, point-source lighting" that works the best for spotting marring. No so far back as to be too dim, but back a good ways. The incandescents in my one garage are weaker, but higher up, than the ones in my shop...and the former show marring better (which can make for some nasty surprises on silver when I think I'm finished).