Editing preview geometry

Hello,

I am writing a component to draw and export some 4d data (xyz + time) in the form of a path. The way I'd like it to work is that the user can draw a 3d path (polyline, curve, whatever) and the component will draw a 'ghost' copy of the same path, but with one end at Z=0 and the other end at Z=1 (or 1000, depending on units / scale) so that each control point has a Z-value between those two extremes. These values should be adjustable, so that when I export the path, I take the XYZ coordinates of the control points of the original path, and interpret the Z-values of the 'ghost' path as time.

To do this, I need to be able to dynamically adjust the ghost path and be able to edit the control points of the ghost path (however constrained to movement in the Z-axis) so that the user can tweak the time-values.

Is this possible through C#? One way I thought of was to do it by passing the control point index values to a graph component to create the time values separately and then merge them when exporting, however I can't seem to get my head around the graph components in GH...

Any tips / help / suggestions would be much appreciated!

Tom