Model imported from Sketchup, lineweights on non-curves faint in print

Ive imported a sketchup floor plan and created a layout with viewports showing plans, sections (using clipping plans), elevations, and perspectives. I noticed on a test print to a PNG file type, that the entire drawing lineweights are very faint except for a few lines. I would like to show a heavy and ideally shaded walls where ever I am cutting, and light lines everywhere else. Upon inspection, the lines that showed up heavier are curves, whereas everything else is a mesh or polysurface. So right now, mesh and polysurfaces print very light, and curves print heavy.

How can I control this? Do I have to do this manually (draw in the curves overtop of the model? Please say no)?

Not totally sure what you are looking for but line weight of sections with the clipping plane are set in Rhino Options > View > Display Modes > [your mode here] > Clipping Plane Objects > Edge thickness:

Post a file or at least a picture if that is not what you need.