Great collection of IWC sports watches of old!
I have been using (and abusing) a regular dial Mark XV on that bracelet for almost 20 years. My GST Chrono had to go though. The blasted titanium didn't hold up when used as a daily no matter what I did, working on the bicycle, pre-flight checking an aircraft etc. Any scratch or dent turned the titanium shiny and looked bigger than it was. Rotor wobble was another issue, on the watch, not the helicopter. Thinking about adding a 3536 where the bezel should hold up better given its corrugated nature.