My goodness, Theresa! Thank you for all of your help. Your final suggestion above of "your favorite solitaire setting of all time" was actually one that I put in the original pool of options. I have seen that ring in person and I actually came dangerously close to buying it on impulse because it's so interesting. But it was eliminated from this project because it's too busy for my friend's taste, particularly from the side view. She would call it "the crazy octopus prongs" or something - ha.
I also kicked around the idea of an enhancer/guard, but she would need a traditional solitaire for that and the height of those are too much for her. She said that anything set as high as my stone (traditional height) would drive her nuts, and I believe her.
I'm working really hard to think like her, but it's so hard to find the infinitely fine line between too plain and too busy.
I said I wouldn't take on the stress of a custom setting... I am failing here... I'm supposed to be writing my thesis paper for school and instead I'm lost in the intrigue of all this jewelry......................