Try The Vintage Rolex Forum(VRF)-best place for that stuff
The insert for 16700 is the same as the 16710 so interchangeable as far as I know.
No idea of price.
Funnily enough I just changed my original 1993 insert for a new one to freshen it up a bit but I am keeping it with the watch
Great watch the 16700-good mix of old and modern.
Post a pic when you get the insert on.