My Caywood .45 Southern Mountain Rifle with vent funneled from the outside does require picking each shot. Like the idea of leaving the copper wire in the vent whilst loading, haven't tried that but think I will.
I use FFFg mainly so I can use the same powder for priming. Yeah, I know FFFFg, and for sure Null B, is a lot faster. Just too lazy to carry the extra horn.
Kinda think 18th century guys, except French military, rarely used separate powder for priming.
Have heard people used a feather to clean the vent in the old days. Have a Kentucky made Kentucky, converted to percussion, that still has the brass tube under the cheekpiece, presumably for a feather.