Hello Stuart C.
I would think such an installation would work well for target work. However, in a hunting situation, two drawbacks come to mind.
(1) Having a peep that far away, would negate the speed of target acquisition that is the peep sights claim to fame.
(2) The "ghost ring" would become a block of steel with a hole in it, and would obscure a large part of your intended target.
I can sympathize with fading eyesight. My 63 year old peepers are slipping too. You will just have to experiment until you find what works best for you. Not liking the idea of a scope on a traditional BP rifle, I have (so far) had decent results with bright red nail polish on the front sight, and use a coarse square notch in back.