Wind Vane steering chain size

[Mike1956]

Am planning to fit wind vane self steering and in the control line there will be a short length of stainless chain running across the cockpit to drop onto the tiller pilot pin. My tiller pilot is a Simrad and the pin size is about 6.5mm. I determined this size with 2 spanners. A 6mm will not fit over the pin and a 7mm will fit over it easily. - must be about 6.5mm!

If someone has already purchased suitably sized chain for this purpose I would be pleased if you would advise me what size to buy.

Thanks

Mike