Here is a hint. Find yourself a large paper clip...the inch and a half type...straighten it out.
Before pouring the powder down the barrel...put the clip into the flash hole and close the frizzen, angle it to the butt-stock of the gun before closing the frizzen. Load as normal, (Make sure the load is FIRMLY seated, not crushed) then remove the clip, and put FFFFg in the pan...no need to fill the pan, just enough FFFFg to come to bottom of the flash hole. I should say that firmly seating the ball with compress the powder in the barrel creating a cavity around the clip inserted in the barrel
Theory; By not filling the pan you are allowing air passage into the flash hole which will draw the flame into the barrel quicker. The clip inserted in the barrel creates a channel whihc gives the flame more contact area with the main charge, thus improving ignition.
I have been using this procedure for decades on a custom built full stock Hawken and the "Poor man's" Kentucky rifle I had mentioned earlier. Ignition in these guns was fast...I stress, FAST!!!!! Both guns were match winners, and gopher rollers. The best the Hawken ever did was a 50 yard offhand target scoring 48-2x out of a possible 50-5x. Not to mention numerous 50-1x to 3X targets shot off cross-sticks. Unfortunately that offhand target took second place to the guns builder who shot a 49-2x with his personal flint-lock Hawken.
Enjoy the rock-lock!!!!!!!!