Springs are usually made of a high tensile strength steel. Clock springs and dipsticks are good sources.
Relative to springs, I made a discovery while removing a stuck rocker arm from a Mark V head. I used a propane torch to loosen the rocker arm, and in doing so found the adjacent spring on the rocker shaft had relaxed.
I made use of this discovery in fixing the coils on my overstretched throttle spring. I compressed the coils with a bolt and nut, then heated it up with a propane torch, and let it cool. It relaxed in the new compression.
I wonder if you couldn’t do something similar to make these latch springs. Put a couple of bolts in a bench vise, parallel and close together.
Start with a steel strip longer than you need.
Hold your strip of steel between the bolts.
Bend the steel around them a little, then heat it up and let it cool.
Or maybe heat it first and bend it second, then cool.
In three or four steps you would have the spring in the shape you want.
