Replacing the black lines on any restore is a real issue. It can be done with a fine brush but it is touch and go as to wether the results will be satisfactory. Marker pens are by far the easiest way to do this but many dissolve and run once the CC is applied. I use a 2 pac epoxy CC which pretty much dissolves anything thats not compatible.
From previous experiments i knew that the best pens to use were permanent water based products - problem with these though is that the tips are very fine - some 0.4mm which means that you have to do several lines to achieve the thickness required. This risks "feathering" around the edges as its hard for the hand to exactly follow its previous movements.
A visit to OfficeWorks has brought a solution.
CALLIGRAPHY pens - these are permanent water ink based pens and a packet of these has a range of tips from 1mm through to 4mm
Some scribble on wax backed paper and CC applied shows that with the right angle on the pen - any thickness line can be achieved and MOST importantly - IT DOESNT RUN!!!
So how do they perform on a painted surface??? Well a quick test on the Bank A Ball PF tells me that they perform perfectly... and at $17 for a pack of 4....you cant go wrong