I've been using Pyrodex RS (FFG) in my Ruger Old Army for a month now with great results, especially at 100 yards (even better than Goex FFFG for some reason). I tried Pyrodex RS in my Walker last week but the Walker didn't like it that much.
Check this out, from an old Colt Industries pamphlet:
"FFG black powder is best for large and medium-size revolvers, and FFFG for the small pocket models, but any grade that is available will work reasonably well."
As a lube experiment I've been using the vegetable spray PAM down the barrel and on the cylinder pins with great results.