If you don't have an easy source of the small diameter shock cord, just get one of those minuscule (short and thin) bungee cords. They are about the right length. Eventually the clips will rust, but you'll get a few years service out of them.
Before the introduction of the HIN in the early 70s the builders' plaques used to report two numbers. The 'hull' number (which counted all hulls of a given builder, not just for a given model) and the 'class' (or 'sail') number, which is what goes on the sails of a boat and is unique for each class of boats. Your class number should be in the 2000's somewhere with a '68, but unless you have original sails or a surviving plaque, you would have no way of knowing as registration certificates may not have recorded that number.
Mine had the wrong year (I presume because the actual age of the boat preceded a change in record keeping in the state) but they entered the sail number.
As regards your plans...
Take it one step at a time. Make sure you are comfortable and relaxed on the boat and can handle common adverse situations with aplomb before inviting any newbies to join you. Not everybody has the same innate response to being on the water and out of their depth - so they may need you to be really competent and mastering the situation or they won't come back.
So far I've only found one species of human who immediately clamor for higher winds and taller waves far in excess of their ability to handle them: teenage boys.
I've had the pleasure to meet more than one woman who is absolutely gung ho about sailing, and I even know one guy lucky enough to have married one of them. An imbalance in enthusiasm seems more common, though, and I'd say if you can interest your wife in joining you, you're ahead of the average. Don't screw it up
