I have a hawke red-redot on my Crosman 1377 which is excellent for close range low light conditions, faster target aquisition and slightly better aiming point than the iron sight. There is only a fixed dot in space but with practice you could alter your aim point by turning the elevation turret, though that would kind of defeat fast target aquisition. If the dot is fairly central and zeroed correctly then at the right range you will hit the target.

On my rifle for low light I would rather use an illuminated reticuled scope of the Mildot type on lowish mag for wider field of view with a largish objective lens to gather more light.

To improve target aquisition using a scope you should try keeping both eyes open, provided your shooting eye is well dominant this is (IMHO) the best approach.

Regards

Chris