Stock a-arms? I would stick with the stock wheels - the 4/1 wheels narrow you up an inch (they are about 3.5/1.5) and an aftermarket 4/1 wheel will narrow you about 1 inch on each side. Any reason you were wanting to go more narrow?
People usually only use the 4/1 wheels with +3 arms so that they stay at or under 50" wide. The 4/1 offset also decreases bump steer and allows for better suspension action because of the change.
I use it because i like to have that extra 2 inches of narrowness, It is not much but if you come up on a bottle neck at a GNCC you make your own line I can fit through a lot of stuff a lot quicker, I will sacrifiece a little bit more body english for the narrowness