West Marine carries 316 stainless wire in different sizes, and APS Sailing is another good option. They have a rigging department and a helpful online guide for measuring wire diameter (measures from high point to high point, not the flats). You might find rigging specs for your boat on that sailboatdata webiste or by contacting the manufacturer, assuming no modifications have been made. Sharing details about your current setup on the forum could help others assist you better. Good luck mate.