I'm trying to insert a reference geometry the finds the apex of a curve.  Below is a screenshot of a spring clip.  I constantly need to know where the apex is located to pinpoint the location where the pressure is applied.  The plane shown below was done with an parallel offset from a central plane, but this won't auto-update if I change the angle or length of the arms.

Does anyone know a way to do this?  It can be a plane (as shown) or an axis the runs across the ridge or even a point at the apex.  Simplified file is attached too.