When I run an USPSA course or something similar I shoot w/ both eyes open , but when sighting in on a small or far away target I close my left eye . I have always shot w/ my right eye but I think I am left eye dominant . How do you test for this ? I was told to hold out your thumb and put it in front of something , then close one eye and see w/eye still has the thumb on target . For me it's my left but I shoot w/ my right .