While I am a right-handed shooter I am also a personal protection instructor, so I have to be able to show left-handed shooters how to do things. I teach them burrhead's method, which I learned years ago from one of the best left-handed revolver shooters I know, and that's what I practice and would use myself. 4V50 Gary is describing, in excellent detail, the right-handed way to do it, down to the end of the first sentence in # "5)". Carry the speedloaders on the same side was the gun. BTW, I index the cylinder by using the flutes. For a left-handed shooter, I would teach to have the right thumb in one flute (closest to the frame), skip a flute, then put the middle finger in the next one (farthest from the frame)(for right handed operation it's reversed, with the thumb farthest from the frame). In between my thumb and middle finger across the top of the cylinder there should then be two chambers in a straight line. When you grab the speedloader or speedstrip with your left hand, put your left index finger tip on the tips of two of the bullets. You can then move those two bullet tips to where you know the two chambers are. Doing this you can reload without looking, either because you are trying to keep track of a threat or because it's dark. Another revolver reloading tip is to make sure the MUZZLE is UP when you hit the ejection rod. If the muzzle is pointed down, one of the rounds/empty cases can rock off of the ejector star and get underneath it. That is a malfunction that cannot be cleared quickly under stress, and the gun is useless until you do.
AR-10:
I shoot a 625 in competition. For IPSC I carry 3 moonclips in front of the gun and 3 behind, although I've seen a number of shooters carry 5 or 6 right across their front. IDPA only allows 2 in front of the hip, but then IDPA stages cannot require more than 18 rds, so I carry two in front and one "Hail Mary" behind the gun.