I use an R&D in my Pietta. My R&D has no safety notches! Therefore, though I can rest the hammer between firing pins, its not "locked in" like a BP cylinder. But, being experianced as I am, I usually load all six when out plinking but at shoots using the conversion I will load 5 if required.
If the weapon were loaded BP I'd suggest he was wrong putting his hand in front of the cylinder. With the R&D this is not an issue. I cock and fire with only one hand so I can't get mine in front of the cylinder anyhow.
It is easier and probably safer to swap the cylinder with the weapon on half cock. The shooter in the video seems to forget that. I load mine in from the right side but it is difficult to line the thing up the first try so it slides around until the pin hits the hole.
The shot group must have been at ten feet like you said!
Even with a shoulder stock I can't get a group like that even at 30 feet. Further, I find that, in my experiance, the .45 LC doesn't group as tight as BP loads will.
I often use the same brand of ammo he does. It's "Ten-X" cowboy ammo. Available in loads from 165 thru 250 grain and IMHO the higher loads should be avoided in this conversion. I use the 200 gr loads.
Sorry guys, I really didn't see this guy doing all that much wrong.