My British friends teach to shoot the rear trigger first to avoid a double, especially with a 40 or 50 caliber double rifle. I find that recoil puts your hand and trigger finger going away from the front trigger. You then have less time setting up for the second shot getting your trigger finger and or wrist/grip resettled causes me to rush the shot. With a sensibly weighted 12 gauge, or a one ounce load with a lighter shotgun or smaller gauge shotgun, if you shoot the front trigger first, recoil automatically puts the rear trigger at your finger tips with no grip readjustment. Switching back to single triggers is not an issue then. When I pick up a 40 caliber rifle with double triggers I do go for the rear trigger first. I saw a double once and that was enough!

Rick