My ideal watch would have a GMT function with a 12-hour GMT hand instead of a 24-hour GMT hand. For example:
To me, it makes no sense that every GMT watch uses a 24-hour hand. My brain is already trained to read 12-hour hands. I can read a normal hour hand a lot faster than I can read a 24-hour hand, which requires either looking at the bezel, or multiplying the time by 2. It's not like that takes a long time to do, but it is slower than a glance. With a 12-hour GMT hand I only have to remember whether the second time zone is greater or less than 12 hours difference from home time, just like I normally have to remember whether it is AM or PM.
IMO we already have an hour hand on there, why not just add another in the second time zone that you can read the same way?
Sinn has the 757 and a couple other watches designed like this. It seems really weird that Sinn is the only company to have thought of this, but they're all I can find. The Glycine Double Twelve at least has a 12-hour bezel, which is cool, but I'm looking for a 12-hour hand. Does anyone know any other examples of dual time zone watches with 12-hour hands?