Speaking of double-wristing of Speedmasters, I was watching documentary footage of the Gemini 3 mission the other day (Grissom & Young). The first thing that caught my attention was when Grissom was being strapped into the Gemini capsule: he had a Speedmaster on a mesh bracelet worn on the
outside of his flight suit. I was surprised that the bracelet could be used that way, although it was also apparent that the flight suits worn by Gemini astronauts were much slimmer in profile than Apollo-era flight suits for example. Later, in film footage of Grissom being hoisted onto the recovery helicopter at the end of the mission, he was wearing
two Speedmasters on mesh bracelets. One on each wrist! Thus I'm led to believe that during the mission he had one Speedmaster for wrist wear and another for outside the flight suit wear, and both remained on mesh bracelets throughout the mission.