Peep sights will serve you well. No need to focus on the hole, look at the front post and target, and your eye will take care of the centering. You can achieve excellent accuracy with a good peep and post.
That's it! The problem with open sights is it is impossible to focus on a rear sight, a front sight, and a target any number of yards away, all at the same time. Just look through the aperture, focus on the front sight, and align it with the slightly out of focus target.
I like peep sights , but I'm pushing sixty now and the eyes aren't what they used to be . When I could see , 2 inch 100 yard groups with an accurate rifle and aperture sights weren't too hard to manage , buck horns would usually double that . I wish I could still use peep sights , but I've switched to fixed low power or low power variables instead , biology demands it .
It gets better as you get older.
Ted