Nice work, Mick. The figure in the wood shows nicely with that finish.
True oil? Great project!
You will have a lot of enjoyment shooting something you built. I prefer a flintlock and the progression of "snap, foosh, bang" as the hammer goes down, ignites the powder in the pan and the ultimate explosion. However, once you get the smell of black powder in your nose hairs, it doesn't much matter how you burn it!

Next thing you know, you will get the itch to build a cannon....don't ask me how I know.

Some folks use Pyrodex with their cap lock rifles and pistols. It does not foul as badly as Black Powder but to me the difference is like that between butter and margarine. BP all the way!
Shooting BP muzzle loaders vs modern firearms can be compared to riding a vintage bike or modern one.
The loading and firing process of the BP weapon is like preparing an old Matchless for starting; a progression of actions. Tickle the carb, get the crank up to the right point, then....a mighty kick and the great explosion. Well, most of the time.

Modern cased ammunition is sort of like hopping on the Savage, hitting the button and off you go w/o much more thought.
Have fun!