I worked on some black-lining on my Zeus battlemech this morning. Tried out a new Artist Loft brush from Michael's, a 3/0 round. They were pretty cheap compared to the Windsor & Newton that I usually use, so I thought I'd give them a try.
The belly of the brush itself is very long, but the toe comes to a very fine point which is itself considerable in length. It took a bit of extra care to control, but the longer belly can hold a lot of paint so it worked out well in this situation where I had the black paint watered down to the consistency of an ink wash (i find for lining the paint leaves a bolder pigment than the ink).
The crimp of the ferrule was glued into the handle. Yes: "was". It fell off about 15 minutes in. The water had gotten under it and dissolved the glue. I put a little super glue inside the crimp and replaced it after I was done. Hopefully it will hold up better next time.
Overall, though, I was happy with the brush. It might be a bit unwieldy for doing lines on a flat surface, but for filling grooves such as these with thin paint it seems ideally suited.