Such work you guys go to!
All my flinters had a flat faced breech, so this does not work for patent breeches.
Truth be known that's probably as good a way as any...and to be honest, the Patent Breech design is not an issue as there's no flat face for fouling to build up on...they're pretty much self cleaning...I've never had any buildup at all.
I do however, keep a cleaning rod set up with a .270cal rifle brush and use it to run a patch down into the vertical powder chamber of the PB to ensure that's dry, then do the same thing with a lubed patch.
Then a Q-tip in through the horizontal channel of the PB with the vent removed...so I could use your approach as well.
Except.....that I use Natural Lube 1000...both to lube-patch wipe the bore before loading, and in all my shooting patches.
I am of the belief that bore butter can/will gradually build up in a bore, and nothing seems (to me) to keep such a bore clean of bore butter buildup than using steaming hot soapy water.
And as a throw-back to years of cleaning T/C hooked breech barrels, I ended up at the same place with my pinned barrels.
My worry whenever I start thinking about using some other approach is...I know this is one way that works for me and "what if" I try something different and screw up a bore...I guess for now, its the old "if it ain't broke don't fix it" thing for me...