Just my thoughts on opposite carry, mainly relative to shooting from behind low cover. This is the only situation I can think of where a left carry, right shooter would be at a disadvantage. A right shooter is going to be lying on, or favoring his left side to shoot over low cover. The horn and bag on his left side would need to be pulled forward in front of his stomach in order to get into it easily, and would be more exposed to the pan flash, and have much less ease of shifting out of the way, than if carried on the right side. The right side carry would also allow easier access and more freedom of motion in re-loading from such a position. Those are just my thoughts, but with that said, I carry left and shoot right myself. My left hand finds things in my bag easier than my right, and I am more comfortable pouring powder into the muzzle with my right hand.