It all depends on your presonal preferance and needs. The .029 pins are larger and can be brighter in low light conditions. If your shots are fairly close and your not shooting at small targets these pins are fine. So if you are wanting the brightest fiber optics you canget and dont mind not being able to pick a tiny spot to aim at Id stick with the larger pins. The .019 pins can still be very bright and being a smaller pin they dont block near as much of the target allowing you to be a more precise aiming spot. I personaly prefer the smaller pins mainly because I do a fair amount of shooting at 50 yards and beyond. At those ranges the larger pins just block to much of the target for me. There is a couple of sights available out there with smaller pins one that I know of is the Extreme Rt1000 I believe and you can get .010 pins on it.