The historical and military way with a flintlock, (especially using cartridges) was to prime before loading Tom.
With a matchlock I am with Flint in post #2.
Thing is, with a flint, the same powder from the cartridge was used to prime, so it made much more sense to prime first, but with a matchlock, fine prime was kept separate so there really was no advantage to priming first.
all best,
R.