You could talk to a rigger, or post on a C&C 35 forum (see
www.cncphotoalbum.com), or just make the assumption that if it's original '80s
rigging, it's time to replace it. As you know, rod
rigging is an either/or proposition: when it fails, it fails completely, rather than giving you some notice with rust streaks or meathooks like 1 x 19 wire.
You also don't say whether you are on the Great Lakes or on salt, and whether you haul and stow the mast for winter, or whether you do fresh water rinses of the lower shrouds, or where you are planning to go. All would affect my answer.