I am with Semisane on this one. I have had a dry hole (forgot the powder) "once I think" (maybe that's all I care to remember also). I just pull the nipple and drizzle a little powder down there and use the nipple pick to pack it in there. Once I have it filled to the bottom of the threads of the bolster/nipple port.. replace the nipple and shoot the dry hole out.

Just that little bit of powder will shoot a roundball 25 yards to the target, break but not pass through cardboard, and bounce it half way back to the bench. I know this because when I did this terrible thing, I had my trusty Labrador Retriever... Number Seven. He retrieved that ball for me. The interesting part (besides the dog finding it like that) is there were slight marks on the ball from loading and shooting.

Honestly, To the best of my memory, I have yet to dry hole a flintlock or an inline. All the rounds I have put down range, and so far I have not ran a dry hole. I watched one young man I was teaching how to load and shoot a muzzleloader, dry hole his rifle ... twice in a row. As he says, I know how to make the thing get the ball out now.

Those items you posted, I have read... really work. What would be nice is to get a zirk fitting for the nipple port that you could hook an air compresses up to. That way you could just unload it in the shop with no problems if you had to or wanted to at say the end of a hunt. Maybe Semisane will figure out.