I either cut circles out of newspaper with my trusty Wad Punch and push them down to the bottom of the shells (this using a Large Rifle primer) or cut 1/4" strips of slightly stouter paper (used ASSRA targets are good for this, since the only holes are clustered around the 25 ring ) and poke the strip under the shell and over the priming punch and punch a tiny circle out as I push home the Large Pistol primer.  (The LPs are shorter, so the wad makes up the excess depth in the primer pocket.)

Either way is kind of fiddly and tedious, but twenty properly loaded Black Powder cartridges take about the effort needed to load fifty Smokeless Powder cartridges anyway, even if the cast bullets are ready to go in both cases.  When you see one big hole in the target at 200 yards, or a 5-1/2" group on a metal plate at 600 yards, five shots off the bench, it's worth the effort.

And yes, those old time muzzle loading rest rifles are even more effort to shoot right.  At least with a cartridge, you can set your compression die (or follower) to a given depth below the case mouth.  Gauging the correct amount of compression by "feel" with a ramrod would take quite a bit more skill, as would seating the bullet, checking bore condition (inside a blind hole, not through an open tube) and all the rest of it.  A lot of top level BPCR shooters are now working with Slug Guns as new worlds to conquer.

I waffled over a Lloyd Resor round ball rest rifle at the Big Reno show for two days, wondering whether I'd have the patience and temperament to get it shooting.  The third day I resolved to make an offer, only to find it sold.  Kind of a relief, actually, though mixed in with regret.

I think somebody on this Forum bought it.  I wonder how he is doing with it.

i have wondered about using a single thickness of nitrated paper  like cigarette rolling paper for wadding to keep fine ball powders out of the flash hole  avoiding Mr ZigZag of course lest it cause erratic bullet flight

The brown coffee filter paper works well. Also like that $5 worth of filters gives one just about a lifetime supply of wads. However, I do not use as my limited amount of testing showed no difference between using and not using primer wads. Like many things in our cast bullet shooting, think this is one of those 'use it if it works for you' ideas rather than a universal truth.