Jay , I just performed this procedure yesterday on a flintlock, thumb piece and hunters star, installed with pins/brads. I do it almost exactly like Taylor ( Taylor your work is AMAZING). I make my pins from the material I make the inlay out of. If you buy inlays already cut this won't work. I put barbs on my pins and before I start taping (LIGHTLY) I put some water or alcohol in the hole, helps slide in and when dry even tighter.
1.) make pins
2.) counter sink inlay
3.) anneal inlay if non ferrous heat to dull red quench in water
4.)drop some water/alcohol( just a few drops) down pre-drilled hole
5.) start taping lightly til into your counter sink
6.) file a little off and tap a little more
7.) file flush
if your going to engrave the inlay , very important that good contact all around in Inlay cavity, engrave lightly, or inlay can pop up a bit . Don't over tap brad into( just make it flush , don't drive it thru the gun) gun, can pop inlay up a bit. Ask me how I know. Steve