I don't trust the safety notches or the pins on C&B revolvers enough to rely on them. I don't see them as UN-safe. However, I know that it is really easy to thumb back the hammer accidentally just enough that the cylinder rotates so that the hammer is now resting on a live cap
Shooting at the range I load all six. I might even load all six and cap them if I am driving right to the range to shoot. I'm not scared of a revolver holding 6 up, but I don't like carrying that way.
What I do if I am carrying a cap and ball where I want to keep 6 loaded but fairly safe, I rest the hammer on the safety notch and leave the cap off the first nipple the gun will rotate to if the hammer is slightly cocked. I still have the powder, wad, and ball in there, just no way to set it off. This gives me 5 for sure and a 6th if I deem I need it. Sure it's slow to cap a nipple in a crisis, but it's a hellova lot easier than loading power and ball AND a nipple in a crisis
Generally speaking, my BP guns are just fun range toys. For defensive purposes, I have much better arms. However, I do sometime carry a smoke wagon with me out in the woods for fun. The 1847 is next on my list. I hope to have one before there are buds on the trees