I am sure you heard this before, but only use black powder in a flintlock. Substitutes just don't work.
So far, the advice given is good. You can set aside the 2f and 4f powders. 3f works fine for both the main load and the priming charge. Using 4f for the prime may provide a faster ignition than 3f but it is likely that you will need some pretty precise measuring methods to tell. You are better served by a good nipple pick to clear the touch hole before firing.
The 2f powder will work fine for the main charge and can work as the priming powder also. As a priming powder it may be a little slower than 3f or 4f.
By the way, the 2f or 4f powders can be used. Use a little more 2f (about 10%) than the 3f. Only use the 4f for priming.
Measure your bore diameter before you select a ball size. If you use lubricated patching for the ball, get a ball that is about 0.020" smaller in diameter than your bore.
For shot, you can get the 0.625 or 20 gauge over shot cards. All you need to start is the over shot cards. Put a nick on the edge or a small off center hole in the cards. Load the powder. Then one at a time load three over shot cards with the nick or hole offset. The hole allows air to escape and makes loading so much easier. Then its time for the desired shot and finally load the over shot card.
Prime your piece and make smoke.