Unless you already have the gated conversion, I'd go with a 6 shot Howell type drop cyl conversion. In fact, as much as I'm an "open top" platform kinda guy, if I had the time to shoot cowboy, I would set up a pair of Rems with drop cyls.
They are fast on the reload (faster than using the gate setup), no fuss switching from cap gun to cartridge (pick whatever category -same familiar base) can be built to show ROA's "how to" (and lighter) with coil springs, excellent "fouling management " . They are an excellent competition platform if they don't bother your knuckles.
Mike