If I read this correctly you are a right handed shooter with a dominant left eye? Why are you concerned about shooting a right hand ejecting shotgun then? Are you saying you are going to try shooting from the left shoulder instead? I assume you shoot shotgun with both eyes open hence the cross-dominance issue as a right handed shooter.
If you are already a right hand shooter it would be much easier to simply correct or "adjust" the issue by either closing your left eye while shooting(not my preferred choice) or by wearing a pair of shooting glasses with an ocular dot over the left pupil to prevent your dominant left eye from being in charge.
I use a Magic Dot on my glasses but any piece of tape will work just fine.
Have someone place a dot with the tip of a black sharpie over the centre of your pupil of your left eye on your lens once you are in your proper shooting stance with the gun properly mounted and you are sighting down your barrel aiming at an object. Remove your glasses, place the tape or Magic Dot on the inside of the lens aligned centred on the sharpie dot then clean the sharpie dot off the lens and wha-la you are good to go...it took me much longer to type that out than the procedure itself.
I like the Magic Dots as they do not have glue. They just cling to the lens and never fall off or come loose even while cleaning the lens. A finger nail under the edge simply lifts them free and they can be reused over and over. You can order them online or some opticians that cater to shooters carry them. And yes I am a right handed shooter who in later years developed a cross-dominance issue and all my guns(except break actions) are right hand eject. Learning to shoot from the left shoulder was not an option for me nor was shooting right eye closed(tried both and both were horrible alternatives).
I just put the dot on my glasses. Problem solved.
https://www.briley.com/p-67003-shooters-magic-eye-dot-system.aspx
Excellent recommendation, thank you! I haven't really shot enough to say that I'm stuck in my ways regarding shoulder position. My left eye is a little stronger than my right, but I don't like the idea of being so limited in choice!


















































