Man  Russ , has it been that long since we first talked about this 

?
 Like Eric ,  I all to often ended up  with a slug when patterning  shots  using a paper shot cup .
 Myself I believe this was mostly do to  having a tight load to begin with  and not perforating the paper .
 But a perforated  cup would end up breaking open in my bag. I even went so far as to try modern cups .
 In the end I found that my  gun shot better without the cup anyway  . .
So really what my paper cartridges end up being is quick loaders .
 I make the paper hull just as Uncle Russ posted .
 However  the way I load them is different as  I make 2 compartments . 
 Once the tube is made , I mark back to the center of the tube .  I then slip  a sizing rod (two piece of the same rod I use to form the paper tube .)  I slip these back into  the tube from both ends  tell the are just shy of center . At that  point I  tie the  tube  off tightly using string . This gives the tube an hourglass shape to the tube . I then mark a P  for powder  on one side and a S for shot on the other side .
 Now  I remover  the two sections of  rod..
 On the P side I insert my  over the powder cards first . If you use wads , you want those in first . Then cards . you cant push them down all the way to the string .  Just go down to about ½ an inch from the string .
 On top of that I put in my powder  load . Then I fold   the end over the powder   in the same way as a normal paper cartridge and  add a bit of glue or wax drip  to the paper .
 Now on the S side I add my over the shot card .  Do it the same way as the  P side and you will find that the two haves will pull up together .
I then add my shot charge . Fold and seal  the end .
Again what this does is give me a quick load .
 To load : take the  end marked P and tear it open . Dump the powder  I the bore .
 Now  tear the paper back and remove the  cards and wad .  If you put them in correctly  they will come out in the right order .
 Once they are down you tear open the S side , dump the shot and pull the over the shot card 
OR if your wanting a shot cup , simply flip the S side over so that the  closed end is inserted into the bore  and the string is up .
 Start this down the bore to the point the string is at the muzzle .
 You can then eath cut the paper with your patch Knife OR  simply grasp the string and give it a yank . Which tears the paper off right above the over the shot card . 
All that’s left is to run the charge home .
Eric . Its been a while since I  played with all this. Ill have to try your  patch idea . Seems to me it would work well . Are you adding the over the shot card before you cut the patch off at the muzzle ?