Instead do this. When practicing sighted fire memorize your grip and postion. Then at night do the exact same thing as if you could see the sights and fire. You will find at the closer ranges it works quite well.
Just snap it up just as if you were using the sights.
but this takes MUCH more shooting to build up the muscle memory and reflex, that = more time + more ammo, of which i dont have alot of either currently.
point shooting takes a bunch of ammo figuring where the gun "points", but only a box or so a month to keep in "shape".