Peep Sight for Ruger American .22
I feel your pain, older eye's and it gets tougher to get sights in multiple plane's lined up with any sharpness. Your peep sight with perhaps a ghost rings is a good idea.
What I did was switch over to reflex sights on my target pistol and 10/22. Very easy to add a rail and attach the reflex sight now you just have a single dot incredibly easy to get on target and even easier on older eye's.
I use a middle of the road Burris fastfire III and both 22 pistol, rifles and a centerfire pistol. You can get different size dots for more precise or speed shooting. Maybe not where you want to go but something to consider.
I am pretty sure a ruger american is setup to take a rail.
Other option easier to adjust but in my opinion bit overbuilt and out of place looking on the american.