Good questions, all. Love it.
1st thing I did was to make my tapered dowel. For me, it was a hit and miss operation. I think I had to make 2 altogether. I use hemlock 1" dowel - was easy tapering with a pocket knife, spoke shave, draw knife or rasp - any of these.
I make the tubes up, gluing the overlap wrap, setting them aside. After they're dry, I turn over the very end and glue, or - tie with 3-ought fly tying thread and trim - I've done both. Then, I measure (stricken) my powder charge and dump that in, drop a ball (sprue filed off, on top, fold the paper over, glue then twist and snip it off with sissors, or tie - your choice.
As Bob found, the tapered 'stick' of powder and ball just sits on the muzzle,waiting to be shoved down.
I used 2 wraps of paper - it has to be snug in the bore, slightly engraving on the lands. I need to choke up on the rod to only 1" out, to start it without a starter - note - it is snug - by the sounds of it, tighter than some guys shoot with cloth patches.
I do not know if it will work well for in deep grooved barrels - rounded or squarish. it works great in smoothbores and my .012" deep squarish bottomed rifling. My hunting firend has a .75 that Taylor built using the Purdey plan form Track that has a .025" deep rifling in it. It has never shot as well as my rifle with shallower rifling. Keith is every bit as good a shot- probably better so that isn't why. He can only load and fire 3 ctgs. before he has to wipe or shoot a squib - CLEANING load, like 82gr. The deep rifling seems to foul badly. I haven't tried to help Keith with this loading problem as he's happy with the 3 shots over his patched first shot.
He's used more than 1 - once. His second and third shots were on another hunter's wounded moose. First shot of Keith's dropped his moose on the spot- typlical for a 595gr. ball through the lights. Jeff's moose took a couple steps and stopped, he fired his .50, moose took off like it was scaulded, which is also normal. We didnt' know, but his shot was low on the leg- no penetration. Keith's paper patched shot on the running moose was too far back, but stopped it- brakes on full. Jeff couldn't load a second shot as his patches were frozen in the -35 temps, so Keith finished it, mere seconds later, with his second paper ctg. ball shot. Gotta love the big bores.