Don't even think of using Pyrodex or some other substitute powder in a flintlock. As for priming powder, you can prime with FFFg Goex and you won't know the difference until you have been shooting a couple of years, and then only if shooting paper targets off a bench rest. There is a difference in the burning time of the FFFg and FFFFG powders, But we are talking miliseconds, and its next to impossible to move your sights in that short amount of time. 4Fg and Null B( Swiss) powders are used by target shooters, to get the fastest ignition.
As to "How many sparks?" the answer can only be one more than "Enough"! Kind of like asking how long your legs need to be when you grow up? - Abe Lincoln said, "just long enough to touch the ground!"
Seriously, the whole point of creating sparks by striking a flint against the steel frizzen is to produce enough HOT sparks that will Live long enough to reach the powder in the flash pan and ignite the powder. That will vary from shot to shot, and day to day.
One spark is all that is NEEDED, IF it does the job. The problem is that ONE spark may not ignite the powder for many different reasons. Terfore, the more sparks you can get to the flash powder in the pan, the greater your chances are that the powder will ignite.
You just don't want the priming powder to ignite: you want it to ignite Quickly. The quicker ignition occurs, the faster the heat created from the burning powder can enter the TH and ignite the main powder charge. The faster that main charge ignites, the faster the PRB is sent out of the barrel, before your sights can move off your chosen POA. Get it?
Now, go backwards in all you do to load and shoot a flintlock. If you aren't getting many sparks, Why Not? Is the frizzen soft? Or gouged? ( chatter marks like you see ripples in a washboard.) Is the cock screw tight on the flint and its wrap? Or is it letting the flint rebound on contact, and bounce its way down the frizzen before cutting steel? Is the frizzen spring putting too much tension on the frizzen, preventing it from popping open when struck by the flint? Is the frizzen pivot rusty and hard to move? Are using those agate " flints", or real flint? Agates are too soft, IMHO, and have a nasty habit of producing fewer and fewer sparks the more they are used. Cut agates rarely are cut along the stone's natural fracture lines, so the way they are cut works against the agate cutting steel like a gun flint will that is made by knapping a spawl off a nodule of natural flint.
There is a learning curve on shooting flintlocks, and you are on the bottom rung of the ladder. Take your time, digest the advice you get, and then ask new questions. We all began right where you are now....... :v
