Is it possible to change tangent edges in Drafting Layout to different linetype syle?
For example DashDot linetype with grey color.
Did you use Make2D to get the curves?
Non, I use Rhino solid or curve modeling than I add new layout and details.
The display modes do not have settings that would let you do this on (poly-)surfaces.
Your only option is to use Make2D and modify the layer properties for the tangent layers.