Sighted my 870 a bit ago with some 7.5 high brass. It is easier with my setup since I can still look down my barrel and see my bead. The thing to remember is that it is opposite to sighting in a rifle. If you are shooting 1" to the right on a rifle you will adjust 16 clicks to the left. In a sense you are saying that I am adjusting my hole in the paper to the left.

On a red dot you are adjusting your dot. So if you are shooting to the right that means your dot is pointed to the left. I had to shoot about 15 times before I got it right!