I have just tryed tamiyas paint marker pen with good results for edges and high rised areas, not so good for the finer detail stuff because the tip is not as fine as I would like it, what type of method or pens most suit finer detailing, my free hand brushing is not to flash.
Look at your craft store for archival pens. These are available in a variety of colors and have really fine tips.
I keep several colors of Sharpies in my paint drawer- the very fine tip kind. I also keep a regular marking pen with silver in it. This comes in handy for several things. i also keep a black available.
The silver ones are great for putting a silver finish on monofilament line for rigging wires for planes of the twenties and thirties that used the shaped stainless rigging.