I've mentioned before a darned good invention called the Merit Adjustable Iris screw-in aperture. The diameter of the aperture (iris) was infinitely adjustable from wide open "drive a BMW through it" down to a tiny pinprick-sized hole, exactly like the apertures in old camera lenses (remember them?). It truly was/is the most versatile appendage one could screw into his receiver/tang sight, making it adaptable for every conceivable situation. Sadly Merit is out of business now but the devices are routinely found on the used market, albeit expensively. But, one of them replaces a pocket full of screw-in apertures of varying diameters, so the cost evens out.
There's also rotating disks with several size holes giving you options on aperture size.
