I use snap on fasteners for my tiller crossbar and tiller extension. So the turning is "done" by bending rubber pieces. I don't have pin/whole fasteners.

I'm sure these rubber piece do stabilize the rudder a little bit. While steering normally I don't feel any resistance but when I dropp the tiller the rudders keep tracking even when the bows are pushed aside by a wave or something.

I think Ronstan call these fasteners "Universal joints"

Wouter