I'm fairly new to the flintlock game but here is what I do. The first thing I did was got my dremel tool out with the buffing wheel and valve grinding comound and shined up the pan so it was like glass.

Before shooting. Clean off the oil from the pan and barrel with a combination of windex and isopropyl alcohol. Dry.

I find if I don't not follow my loading process exactly everytime I may get away with 2-4 shots but more than likely, I will not.

1. Wipe flint, pan and frizzen with alcohol windex patch. Swab barrel afterwards with same patch.
2. Dry flint, pan, frizzen and barrel with a new patch. Save for next shot.
3. Plug vent with pick, paperclip or whatever you like. Close frizzen.
4. Charge barrel, load ball
5. Remove pick. Charge pan. My pan on the GPR is about 1/5 full banked away from the vent. Close frizzen.

I use 4f as prime and either 2f or 3f main charge and a RMC vent liner.
Works for me but as always, your mileage may vary.

Good luck.

HA