Excellent. I like both the cat's paw and the butterfly loop. The cat's paw is large but pretty and the butterfly loop is small and pretty as well. Thank you for the welcome, and the suggestions. The cow hitch wasn't a lot of use primarily because of the cord I'm using, I think. The "springiness" I mentioned earlier is one part of it, the cow hitch doesn't snug up as nicely as in other materials. Another part is that the ring is a wide band (it's jade, not the standard narrow gold band). This, in combination with the large diameter cord (relative to the size of the ring), means that when the standing ends (or is that standing and working?) are pulled apart to go around my neck, the knot widens out a little. It doesn't come right off, but it will if it gets nudged in just the wrong way. Just the movements of my body could be enough for me to lose the ring, given years of "attempts". I thought the cow hitch would be perfect until I actually tried it.
As for the cord, it might be smart to use something different, but I couldn't think of anything with the qualities I wanted. It's nice that it's a fairly large diameter because it doesn't cut into my neck. It's very strong, so I don't have to worry about it breaking easily. I'm really hard on necklaces. In fact, on almost anything I'm wearing. I understand the worry here, that it will be stronger than my windpipe, but I figure if I tie it on with little enough slack, it won't get me. Rattail is very durable, my husband has been wearing his engagement ring on his original strand for at least five years, and it only needs replacing now. He never removes it, for working, for showers, for anything. Finally, it's kind of a pretty kind of cord, it has a nice sheen to it. If someone else can tell me of another cord that is at least 1mm in diameter, strong and durable, and preferably kind of pretty in a simple, dark, single-color kind of way, I would try something else.
For now, however, I think the problem is solved. I will try the cat's paw first, and then I will try the butterfly loop, and see which I like best in practice. Thank you very much.
Incidentally, I'm now fairly happy that I couldn't find my knot book to help me out with this problem. You guys (and/or gals) are great!