I would not do this between color coats of certain paints. This will loosen the paint and cause a mess. Right now I am using 91% ISO to strip off Alclad Lacquer paint.
Great idea on a unpainted model, which I suspect ShutterAce meant.
Yes I will lay down a strip of silver paint to see the seam with. I am afraid of sharpies on models, I have seen too many where someone does pre-shading with a sharpie and it bleeds through the paint.