I have the Lyman peep on my GPR. Retired is spot on.
Use the tiny hole for sighting in, and if its really low light in the field hunting, take the aperature out altogether. The POA/POI will be the same.
Try it a few times to be certain you,re aligning everything properly, or maybe become accustomed to using it. Vastly superior to standard iron sights. Just require a bit more light.