If the current spring proves too stiff, you could always remove a little material from the edges. Using a half round mill file to cut a very gentle curve in either side, will relieve the spring a bit, making it softer. This hourglass shape when looking down may prove invisible to the untrained eye, appearing totally straight. Any material removed from the spring will soften it, I recommend working the edges, because your spring looks nice and wide, and you could probably split it, make two, and both would be far stronger than needed.