Linda I had similar trouble when I bought my 1975 CHB 34. I found it easy enough to buy a few springs that were close enough to the ones on the wipers to fit, but added the desired tension. I forget what the springs were for - not wipers for sure - and I had to buy a pack of about 5 from memory. I think I still have 3 spares rattling round in my tool box, even though the boat is long gone now.
If you were in the Dunedin I used to live in, NZ South Island, I'd offer to send them to you. but as you're in that other Dunedin in the US, probably not worth it. But any decent hardware store would have them.
PS. I suggest you try to get the longer blades to fit while you're at it...you'll definitely need good tension to hold those to the glass.