Thanks for taking a look everyone.
@Oldtool - I know that a lot of people do sharpen pin gauges to a knife profile because it can help prevent the point from wandering when marking with the grain. Personally, I don't do that although I'm not knocking anyone who does. I've found that concentrating on technique is important when using pins though. The trick when running a pin gauge with the grain is to make the first pass really light and not try to push the pins into the grain too much. Instead, focus on keeping the stock pressed against the wood. On subsequent passes, the pins will then tend to follow the track created on the first pass.
Regarding using needles, I'm not sure they would leave a very visible track. I don't know about you, but I find as I get older I need the scribed line to be a bit wider and I often make it a bit more visible by running over the track with a pencil.
Andy -- Old Chinese proverb say: If you think something can't be done, don't interrupt man who is doing it.