When I was a kid, although my Dad tried his best to teach me to shoot with both eyes open. Regardless, I always shot my bb gun with my right eye only.
Lately, I've been working on correcting my horrendous left eye dominance.
One thing that I found and haven't seen mentioned (maybe for good reason?) is when shooting a pistol, I turn my head just slightly toward my dominant eye, leaving the gun further into my nondominant eye's field of vision. The double image will disappear. As I work with this, I find myself turning my head less and less all the time.
Has this worked for other people or just for me?