Hi Smylee!
After shooting some years ,my cousin we discovered he was a right hander left eye dominant . It explained why figure his shooting was a kind of hit or miss fashion at the local matches.
It took him about two years to make, the transition . First he started shooting his existing rifle from the port side , but he really wanted a rifle that would fit him .So we gathered up some parts , a .54 cal barrel , a Beck stock from Jack's mountain and sent the lot to Mike Compton in IA to stock. Now he has a true left hander and finally a rifle with enough length of pull (6'4'' height)
If it were me ,being older, I'd be a bit unhappy like you as all my keeper guns were fitted to my dimensions.
So if this were my problem ,I think I would build a compromise rifle no cast- off ( or on as the case may be )rifle ,no cheek piece, but leave the lock on the right side with a short tang . That way if I wanted to bend it there wouldn't be an issue with the hardware. My cousin likes his new left hand rifle but finds the left hand lock a pain to cap as he is still right handed and that his where he's still used to looking for it .
There were some historic rifles with cheek pieces on both sides I recall seeing.
Maybe for one gun frontier families who had to share?
If you're a flinter guy I would still use a right hand lock . I have found as a rightly ,shooting a left hand flinter doesn't block my vision so much .Might even help my flinching.
My take away from this is a lot of new shooters don't know about eye dominance just like my cousin .Helping new shooters figure this out early is critically important to shooting success.
While helping run a range day for MN gun safety certification on the shotgun range the first thing I checked was the eye dominance of these new shooters .
One of the young men as a rightly with left eye dominance . He was a bit upset when I told him he had to shoot from the left side . At least he left aware of the problem . My cousin didn't figure it out till he was forty , his dad just assumed as a right hander he should shoot from that side likely not knowing about eye dominance .His dad was a great duck hunter but he was never deep in the weeds re teaching shooting .
Sorry you're running into this problem Smylee .
Eye issues and getting old isn't for the faint hearted but at least you know the issues and are formulating a solution.
Best wishes for your future success.