I am left eye dominant and right handed. I shoot with both eyes open, but if the ghost image bothers you, try this....
1. Put some chapstick or lotion on your right index finger.
2. Hold the gun in your weak/left hand hand in front of your LEFT dominant eye. (yes, with your left hand, just for now).Make sure you are looking down the sights with your left eye.
3. Now, close that left eye, but do not move the gun at all.
4. Take your greasy right index finger and cover the gun and just the gun by putting that index finger on your right eyewear lens. This will have blocked out the ghost image of the gun that the right image sees.
Either always put chapstick here, or for a more semi-permanent solution, put a small piece of scotch tape there. This will help you use your left dominant eye and ignore the ghost image from the right, but still keep your right eye available for looking at other things through the lens. When you shoot freestyle with both hands, as long as you index to the left dominant eye, you should be ok.
I tried to use my right eye since it "matches" my hand and it never worked out. It took me about a week of dry fire to adjust my index so that I lined the gun up with my left eye every time again.
Don't fight the dominant eye.