Widen that flashpan with a dremel tool grinder, leaving only 1/16" around the outside to make contact with the bottom of the frizzen when its closed. That give your sparks a bigger target. It sounds like you are using flints that are too long, as that is the usual reason sparks hit too far forward to ignite the powder. Chip or cut the edge back and you should have good ignition. Polish that pan mirror smooth, so it won't hold powder residue after every shot. A slick finish makes it very easy to clean with just a swipe of a cleaining patch. By widening the pan, you can get your thumb down into it to clean it with that patch easier, too. Then wipe off the underside of the frizzen, and the underside of your flint, and you are ready to reload.