Yep, another one of my dream-guns. Perhaps I'm a bit of a purest, but I'd stick with BP. It's more "fun", and a squirt bottle of Windex will clean it right up in about the same time as cleaning it after shooting smokeless in it. If you use compressed powder (BP) loads it will burn cleaner and require less cleaning.
I'm not sure that it's any advantage to leave a pistol dirty for a longer period of time using smokeless. ?? On the other hand, a BP revolver can be left dirty, in a low-humidity environment, for a long time. I'm not sure why anyone would do that, but I've told the tale before about a friend of mine who shot his 1851, put it in his underwear drawer, and six months later sold it to another friend of mine. There was not a spot of rust or corrosion on it. Was just dirty like it had been shot an hour ago.
Also, without the nipples to contend with, and all the nooks and crannies involved with cones, clean up with a cartridge gun is a snap.
As someone mentioned, shooting smokeless in a BP pistol "just ain't right". (paraphrase) And the easy way is seldom the best way. I would suggest a 200 grain lead bullet over just enough BP to give about 1/16" compression. Or, however much compression you can get without deforming the bullet.