For Target shooting/practice I use 17 grains of Swiss 1 in my Hege Remington, topped with 11 grains of genuine American Cream of Wheat (It's a cut off nozzle that used to be 15 grains). This allows the .457'' ball to just fit flush in the cylinder. Whether this improves accuracy at all is a matter of opinion.
I use Castrol white grease to lube the ball, with a plastic syringe, putting just enough to seal around the joint between the ball and the cylinder. I usually find after the first shot the majority of the lube has vanished in the flash! So far, touch wood, I have never had a chain fire. My best 10 from 13 at 25 metres is 92. Like I said, despite everything being 100% consistent my scores are usually in the low to mid 80's with low 70's being the sign of a bad day!
Interestingly, I watched a Cap n Ball video where he shot a Pedersoli Remington with 9 grains(?) of Swiss! You could very near see the ball in flight!