I am new to the forum and know nothing of building muzzleloaders. I am also no expert on wire inlay. So I am not claiming this is the best way to do it, this is just the tools I have made to do it. Firstly I got a few xacto knives and cut them down, maybe by half but it’s whatever feels good to you. Then I used my drill press to bore a hole in some golf balls. You could turn handles or use a dowel, whatever works for you. I epoxied the xacto handles into the golf ball holes. The secret, if there is one, is to save your used up blades, then use a grinder like on a rotary tool to get the shape that fits what you are doing. You must be careful not to overheat the blades and loose the temper. I shape some wider ones (size is relative) for straights and the tighter the curve the narrow the blade is needed.