With your beautiful collection I can see how difficult it would be to choose the right piece to add, especially with the stock/SO/MTO situation. I turned 50 last year and wanted something special to mark the milestone. I have spent the year since encountering major medical problem after major medical problem. Several surgeries later I am in a YOLO mode. If I was ever offered a Tiffany Owl on a Rock (the star sapphire or black opal) I would buy it in a heartbeat even if it sat in a box on the counter for me to admire most days. Obviously, while being fiscally responsible.
Meaning, IMO, choose something fabulous that you love, even if you don't wear it every day or get a fantastic cost-per-wear. Sounds like the RG bracelet/watch is the closest to that on your list.