Regarding flintlocks, I'm curious which powder substitute is preferred if Black Powder isn't available ... T7 comes in granulation sizes up to FFFg.
Been starting to feel the flintlock fever also, though I'll always have aortic room for my modern inlines. Been eyeballing the Kibler Long Rifles often mentioned on our sister site, The Muzzleloading Forum.
I have no hands on experience with flintlocks so take this with a grain of salt.
From what I hear, keep the substitutes out of your flint lock. BP is more easily ignitable than the substitutes and the consensus is the subs wont work well, or at all in a flint lock. I'm sure a foul weather hunting scenario would make this even worse.
I plan to mail order BP to get going