Since this might come up in a search again later and since I seem to get contacted on this fairly regularly, when I wanted springs, none were available. I had some undamaged springs and knew of a small batch prototype spring place near me in Michigan. My son's place of work does business with them. I took them the spring, and they created a few for me to inspect. Basically, the spring rate is a function of the diameter of the spring wire, Diameter of the spring when coiled. and the length of the coiled portion. The samples were spot on. They used the same spring material as the original. There are not many spring wire variations to choose from. I decided to lower my cost by offering up a group sale hear. Mylstar brought everyone's price down as he ordered a bunch to offer for sale. I made enough to cover my springs and my fuel as there were several back-and-forth trips. I hooked Mylstar up with the company as they gave me a production number to use if I ever reordered. He told me he would not advertise on KLOV to not compete with me. I told him it was a one-time deal for me and he was free to do as he liked. I know the shop closed for a while or an unknown reason and we had a discussion about it. I don't know if Mylstar still gets his springs from the same spring shop but I have never had a negative comment on any from my run. I can't say who has the best springs, but I liked the ones I had made up and they are the same ones Mylstar at least started with. I would be interested to know if he got any feedback on them and if he is still getting them from the same place near me.
Either way, my pet peeve is seeing the yoke hanging off on way or the other and having a dead spot with no spring tension in the middle so choose carefully.