I’m not satisfied with my factory sights. They are hard to see and I don’t shoot very well with them. I’d also like to have night sights if I make a change. What do you recommend?
Since it's not feasible to change to different sights every time you want to do a different shooting job with your pistol or shoot in different lighting environments, it's smart to figure out what features give the best utility for any use you need to employ your pistol to do.
The best all-around iron sights for a self-defense handgun have a front blade width of .125-.145 with a tritium lamp and a colored ring around it, either white or as close as you can get to it. Also available are Trijicon HD front sights with a bright orange of yellow photo-luminescent ring around the tritium lamp.
Either way gives you a "contrasting feature" with a night sight lamp that stands out in your sight picture in any lighting condition. If you question the value of a tritium lamp, go do some shooting in twilight and semi dark conditions. Also notice how much easier it is to find your "night stand" gun in the dark.
It is crucial that the rear blade should have a notch width at least .020" wider than the front blade width (.020" for Gov't Models, shorter guns need a little more width in the notch, the shorter the pistol gets). A significant "light gap" is the single most important aspect of sight design for fast employment and being able to see with aging eyesight.
If you want tritium lamps in the rear (and I think they are worthwhile), they should be installed below flush, so you don't see the lamps in daylight, just in the dark. You definitely do not want a white ring around the lamps. White rings around the rear tritium lamps just put too many things in your sight picture, competing for your attention and taking clarity and the ability to focus away from the notch and post.
Square notch or U notch in the rear sight blade? It's a totally personal choice. I can use one as well as the other. Think about this though - You don't aim iron sights with the bottom of the sight picture, you use the top edge. So if you can focus on your front sight, what does it matter how the bottom of the notch is configured? Again, there's no wrong decision and that's why I make the both ways.
Some folks with deteriorating vision that have trouble getting focus, like a round colored feature on the front sight with a U notch on the rear. They come closer to seeing iron sights with that combination. About the only thing that makes me stick with square notches myself, is that I feel that a square notch allows just a little more light into the sight picture, which again is the single most important thing that a set of sights should do.
This is the philosophy that is in play with the design of Harrison Design sights.