The Kemper Fluid Writer is the pin stripping tool of choice for many of my colleagues. It come in 2 sizes. It helps to use pin stripping paint because it has more pigment for better coverage in one pass. Another trick is to round with emery (sandpaper) the tip so the edge is not so sharp and won't dig into the painted surface of the tube.

The paint doesn't start to flow until the tip touches a surface. It's magic!

It is helpful to think about how to erase a little blob or slightly too wide a line. I do this a variety of ways including with a toothpick or a paper towel dipped in paint thinner. Sometimes my finger is supporting the paper towel and sometimes it is some kind of pointed object.