Mike, what you have there is a self-priming flintlock. Shooters don't like to see this now, but back in the day, it was considered an advantage because it eliminated one step in the loading procedure, i.e. priming. My only flintlocks at this time are smoothbores, but most of them have 5/64" touch holes. I think the vent on my Charleville is .078". I use Goex FFg and have not noted any leakage.
If you don't want it to self prime (and they didn't always, even back then), you put a plug in the touch-hole and just pull it out when you are ready to shoot. This keeps the main charge from absorbing atmospheric moisture, also. This was referenced in Magné de Marolles' An Essay on Shooting, from 1789 (if I read the Roman numerals correctly...): "But, whether the practice is to prime before or after loading the piece, it is highly proper, after every discharge, to prick the touch hole, and what is still better, to guard against all remains of fuse or squib, by inserting into the touch-hole the feather of a partridge's wing, which will not only clear it of the dangerous remains, but, if the piece is delayed to be re-charged, will take away all humidity that will be contracted there" (p. 194).
At this point, it may be a good time to insert "the Audubon quote," in which John James Audubon, circa 1810, described his host preparing to go raccoon hunting:
"… He blows through his rifle to ascertain that it is clear, examines his flint, and thrusts a feather into the touch-hole. To a leathern bag swung at his side is attached a powder-horn; his sheath-knife is there also; below hangs a narrow strip of homespun linen. He takes from his bag a bullet, pulls with his teeth the wooden stopper from his powder-horn, lays the ball in one hand, and with the other pours the powder upon it until it is just overtopped. Raising the horn to his mouth, he again closes it with the stopper, and restores it to its place. He introduces the powder into the tube; springs the box of his gun, greases the "patch" over with some melted tallow, or damps it; then places it on the honey-combed muzzle of his piece. The bullet is placed on the patch over the bore, and pressed with the handle of the knife, which now trims the edge of the linen. The elastic hickory rod, held with both hands, smoothly pushes the ball to its bed; once, twice, thrice has it rebounded. The rifle leaps as it were into the hunter’s arms, the feather is drawn from the touch-hole, the powder fills the pan, which is closed. “Now I’m ready,” cries the woodsman…."
Journals, Vol. 2, (1972 reprint), page 492.
Note that the rifle carried by the hunter in Audubon's description "self primes" when the feather is withdrawn.
However, safety is a concern here. You don't want an accidental discharge while loading! That's exactly what killed Walter Cline, although I think he was loading a percussion rifle that was capped. You need to make sure that the half-**** position on your flintlock is very secure, especially if you load with the pan closed. Also, it is a good idea to put a leather hammerstall on your frizzen while loading. This is a little leather sheath for the frizzen that keeps the flint from striking steel if the **** falls accidentally. I took musket training at St. Augustine some years ago, and while we shot only blank loads with paper wadding, the loading procedure included priming from the paper cartridge before putting the main charge in the barrel and ramming the wad, but with the lock at half-**** and a hammerstall on the frizzen this was considered safe.
If your rifle leaks powder through the touch-hole, I think it's a good idea for you to use a hammerstall on the frizzen while loading. I made a couple of extras, and if you PM your address to me, I'll send you one. These are easy to make from scrap leather. I don't know the dimensions of the frizzen on that Kibler lock, but the extra hammerstalls I have were made for an L&R Queen Anne, which is also a fairly large, round-faced English lock, so maybe these will fit the Kibler, too.
Notchy Bob