Another option, and one that I used. Rather than file the front sight narrower, I bought a rear sight that has a wider gap. When I focus on the front sight I can see a decent gap to center up with however when I focus out on the target and let the sights blur I get a solid black when I am lined up perfect. It took me a while to find the right combo, I really think the gap size is a personal decision, based on your grip, the gun etc.