I've tried the "stay on" paper patching but it gets shredded in the bore so has a rough uneven surface. For me it didn't work. Better to shed the patch I think but smoothbore shotguns are not BP paper patch rifles so there is no rifling cutting patches and "confetti" at the muzzle. I think the patching has to come off cleanly much like a sabot. The other issue is that the patch has to survive rubbing on a rough hull, opening a crimp and the jump through the forcing cone.
Personally I think a full bore slug or a wad slug like the Lyman sabot slug and the Lee Drive Key slugs are the way to go. In the end the fit is an issue. That's why I decided to size down my Lee Drive Key slugs so I could then patch back up to snug fit for a specific bore diameter. So far the sized paper patched Lee slugs seem to be doing reasonably well but they need more testing.
Longbow