Anyone use Sig 365 or such single rear glow sight, that sits flush into the slide and uses no additional front sight? I think you have to center a tiny circle around until the glow fiber optic or whatever shows inside it; then you can aim with it then being exactly parallel to the slide . You’ve seen the ads/vids. Seems centering that tiny circle around at arms length would b slow for older or not so perfect eyes. Gimmick? Or is it truly a new and revolutionary mousetrap that your eye picks up much quicker and allows faster, more efficient aim n’shoot than traditional sights?