Here's a couple of pictures of the stencil process. It's nothing complicated. Matter of fact, I have pretty much polished off the bottle of port just before doing it.
First I lined up the brass and the copper layers. This was easy to do as I had the foresight/common-sense to drill the mounting holes before doing any of the detail work. Then I slid in and aligned the stencil in the center of the cut out brass hole. Then I taped down the stencil so I wouldn't accidentally move it while removing the brass.
Then I masked off the edges so that there was no copper exposed. I removed the tape holding hte stencil in place from the center area. At this point it was ready to mark/paint.
I choose to use some old white Citadel model paint. Why did I use white? *shrug* No particular reason, I just thought it would give me an idea of what it will look like when I'm finished.
On a side note, you are what you eat. I'm pretty sure brass dust in your port isn't good for you... but I really didn't want to waste good port.