I've transitioned to narrow as I've gotten (slightly) gooder at shooting, and it does help for precision. Takes some work though, because you can lose tiny sights easier when you're flailing around.
With elevation adjustable sights, I really like a 6 o'clock hold PoA for USPSA type shooting. Just covering the general area where I want the bullets to land with the front sight blob resulted in way too many hard cover mikes and no shoots on partial targets, and I was spending too much time dicking with getting sights aligned horizontally. Knowing the hole is going to appear an inch or two above the front sight at ~20 yards if I do my part trigger-wise makes my brain happy. If I'm sloppy with the trigger I can usually see where I'm missing on long steel too, since the splash is somewhere above the rear/front sight plane.
Any of you fuckers have useful opinions on this?
it definitely helps for long/tight shots. I'm running a 3mm on my match gun and a 2.5mm on my backup. I'll probably go to 2.5 on both after nats.
Metric is dumb. Shove those millimeters up your ass and wiggle them.