Thank you for posting the picture! It looks like it's about the size of most of the cocktail rings I wear (typically on my middle finger). I think I'm going to go middle - like you said, it's easy to size down if I change my mind. I'd love to see a picture with it on the middle finger, too...
(No pressure, though!)
ETA: Never mind, it is on your middle finger in the bottom one, isn't it? I think it looks good there!