I've had good luck with my old eyes and aperture sights, but I needed to always add a hooded front sight or globe sight. The "ghost-ring" effect is full-on blurry mode for me, but my brain picks up the two concentric circles pretty quickly.
This mountie has a Williams rear, my long rifle 39A has the Lyman rear sight, both have open-top front hoods over a polished brass bead (45 degree bead face catches plenty of reflected light). I tried the skinner sight, but no quick elevation changes made it a no-go for rimfire silhouette shoots
the long rifle set up for silhouette;
..proof of my blurry sight, I thought these were in focus..,