Obviously, you now understand how important it is to order the right sized flint. Do so. You have time for them to arrive by Christmas. Next, square the edge to the face of the frizzen, by opening the frizzen up slightly so that the edge of the flint will strike the bottom of the frizzen face, or the back of the heel of the frizzen if you look at the frizzen from the side and see its similarity to a human leg and foot. Hold the frizzen at the correct height, with the side of your left thumb, cock the hammer back to full cock, with your right hand, and then pull the trigger. a new edge will be chipped off in one blow across the entire width of the frizzen. The only adjustment you need to do to the flint in the jaws of your cock is see that its aligned sideways correctly, so the inside edge does NOT scrape barrel, see that the flint is not too long, so that it will smack the bottom of the pan when the hammer is down, and then make sure your cock screw is down firmly on the flint and lead or leather wrap. If you use leather, stick with thin leather, like what you might get using the tongue of an old wornout shoe., or even the leather from a well worn out wallet. If you use lead, make sure its also thin, about 1/16-1/32" thick, and drop the cock five or more times to allow the lead to flow and fit snuggly to all the smooth curves and dips on the flint, and then tighten that cockscrew down again.
You did right by banking the priming powder away from the touch hole, but remember to run a vent pick into the barrel through the vent hole to clear a path for your flame and heat when the priming powder ignites. Ideally, you want the touch hole slightly higher than the top of the pan, and it never hurts to grind out the pan to make it wider, and shallower, and then polish the heck out of it so it is much easier to clean, and lest likely to hold dust and crud that will absorb water from the air between shots.
YOu don't hve to use 4Fg powder for priming powder. Instead, use whatevery Black powder you load in the barrel. That saves you from owning two horns, and having all that stuff rattle around when you are humping it through the woods.
Work up a load for your gun on a bench with a rest, and ask us when you actually have your gun, know the caliber, have measured the land diameter( bore) and broove diameter of the gun, so we can tell you exactly what size round ball you need to buy for it, and what thickness patching will work the best.
In the meanwhile, read the posts here, and study up on patch lubes, and gear. Go to Dutch Schoultz's website,
[url] www.blackpowderrifleaccuracysystem.com[/url]
and order his system, Its the best $15.00 you will ever spend anywhere, and it will shorten up your education on how to find that accurate load for you gun so much it is almost a sin to make that much information available in one source!
Good luck to you. And Welcome.