All told the 2597 is an immensely cool and very
link rare watch that can also be found double-signed by Tiffany Gubelin and others. Values are high and climbing with A+ examples like this one offered by Phillips in November of
link 2017 selling for serious coin CHF 540500 before premium. Those curious can check out these lots including this double-signed Series 1 example on a bracelet offered in 2019 via Bonhams or this more patinated Series 2
link example from Phillips sold in May of 2018.