I have not tried sabots in BP revolvers.
The only experience I have had trying to push plastic with BP was a fiasco.
Back in the 70s, I tried using plastic wad columns in a muzzle loading shotgun with bad results.
The plastic fouling in the barrel was unbelievable. I mean two foot long strings of the stuff, not to mention the work it took to scrub it from the surface of the bores.
Inspection of recovered columns indicated extensive melting of the over powder seal, which led me to conclude the Black stuff burns at a higher temperature than smokeless powder.
Maybe plastic used today is better than 40 years ago, and I only tried one brand at that time, but I have never tried plastic in any BP gun since that experience ?