Sheesh! Now that is a serious challenge! They are nearly unobtanium, but I will give it the old college try.
Occasionally, I make my own ring lugs from a small bit of brass foil which I use to clean and polish between the tines of fountain pen nibs. I cut a small rectangular piece and punch a hole in one end with an awl or similar pointed tool. Otherwise, I make a very small loop of stranded lead wire formed around a pin or nail, and tin (solder) it so it is stiff and works like a ring lug. I have even filed the head of a brass screw in the edge of the capsule and soldered the wire directly to the bare screw head, although this is not my preferred method. Soldering to the brass capsule, itself, takes too much heat and I fear that would damage the capsule internally. But soldering a small screw in one of the mounting holes works well, as long as it is polished and there is no lacquer on it.
Just MY take ... your mileage may vary. James -K8JHR-