As always great work and thank you for sharing. I have started printing this already but it seems that the gear is missing?
On another note and for others who may make this. I have also printed one of the openhand models and have come to the same conclusions as you. But I did not have the urethane when I printed mine so I used silicone sealant in its place. It seems to work very well and is very sticky, but takes a long time to cure.
Thank you again