How about this?;

One can simply make a nurbs-curve by klicking the numerous vertices on the spring-objects of yours.

It's not done in ten seconds, but it cannot take forever etither.

If the curve need modification;
1) Make a locator aligned to the center of the spring.
2) Set pivot point of the curve to the locator and scale the X and Y axis.
3) Leave the Z axix alone. Simply move the whole curve a little down or a little up if this is needed.

Just some thoughts.