Some guys don't mind buyin', some do! I used clips for most of the connections but I welded the terminations where the wire came back to itself and I put that weld where there would would be no stress on it just for the reason you mentioned. Yes, they would be very complicated to build, that's why I went to a an old mattress spring for starters. The mattress spring had two of the of the dimensions the same , the width (38") and the thickness. Granted, the original spring was tapered to the rear. I used garage door cable to pull it down to duplicate what Henry had originally installed. It fits, it works ! Agreed! Snyder's does a nice job on its product. I bought a front seat back rest ($119)and picked it up at Hershey. They will deliver to shows. I bought the Hog Rings and connectors from a local Body shop supplier. They are US made, Aveco. Less that $10 a box. The Hog Ring pliers you almost have to use. I bought mine in a flea market for about $2. Because of the problems I'm having with this computer and it's picture program. I can't display my pics of the finished piece. BTW I used to earn my groceries by being a Mechanical Model Maker and our thing was to make what we needed, not go out and buy it.
Terry