Lines between surfaces

I’m trying to create a perpendicular line between surfaces within this volume (where its protruding inwards) at the moment where the surfaces are closest.
I’m hoping then, to create a curve through all the midpoints of those lines.
Basically, trying to get the interior skeleton of this volume as the resulting negative of the Boolean difference operation is still not what I’m trying to sculpt.
thank you,
rpPlease Help Me.3dm (1.1 MB)

I found only this thread on finding the minimal distance between surfaces: Minimum distance between two surfaces that do not overlap. Maybe @menno can help if he compiled it in a useful plugin.

What I describe in the other topic is not available in a plug-in.