The two sights I pictured, sharpen the front sight, just as any peep does.
You are indeed lucky your eyes are aging such that you can see both the sight AND the target in sharp relief. Normally it's one or the other, although with most people, the target is still very good when the front sight is sharp. Anyone with firearms training will tell you that the front sight is the important sight to have sharp, while the rear and target are somewhat fuzzy. Having to wear a 1/2 of full diopter to sharpen the front sight as some of the guys are having to do past 40 yrs. old, usually makes the target even blurrier, but it's better than having all 3 blurry or not being able to shoot at all without magnifying glass as in a scope. One friend who had diabetes and who is now deceased, had to have at least 4 X magnification to see 100yards.
Most or at least many smoothbore round ball shooters are in the eye's-getting-bad stage. Only having the front to contend with, makes aiming easier for them. On gong targets, many of Rendezvous BC's smoothbore shooters always score higher than most rifle shooters. In other words, to beat all of them, one must just about "ace" every trail. All are doable, but having fun the night before, usually takes a toll.