Looked at the pdf, it looks like the bungee is 5/16 but it dosnt spec.
It also specs an eye peice for the attachement to the pin at the front of the tiller tube. is that something that murrays sells?
The tiller connections on my boat are in mint condition, nop need to replace them.

By the way, I dont see many posts regarding the 5.7 nacra. arent there many of them out there?