I won't give an opinion on the best one shot stopper, because I don't have to. Stopping index is an interesting concept, but the FACTS ARE, the 125 grain jacketed hollow point in 357 magnum has the best one shot stopping record in law enforcement actual shoot data history. This data goes back to the 60s and is collected NATION WIDE from law enforcement agencies for the FBI.
I have used the 357 magnum 125 grain described in a shooting, and a 200 grain hollow point in 45 acp in another shooting with very similar circumstances. Although both performed and I obviously won, the 357 mag did not fail but, the 45 acp was marginal although successful, but just barely.
As far as concealed carry, I personally carry a J-frame Smith Model 60 in 357 mag. with said bullet, and trust it completely. I have only used the Model 60 to stop an 80 pound Rott but, after losin an ear it did change his mind about my little Jack Russell, and retired to his place of residence with bad hearing and, a missing right ear. A bad shot on my part, but my point was made to both the dog, and the owner.