line weights in dwg to pdf conversions

[Pierre_6.1]

I regularly convert AutoCAD dwg files to pdf files.  Some of the lines in these drawings have bolder lineweights, to emphasize them.  When I view the pdf files in Acrobat Pro, the lineweights all default to a single width.  However, when I preview these same files in gmail, the lineweights display correctly, so obviously, the lineweights were saved as part of the pdf's.  Is there an Acrobat display setting that I can change to correct this issue?

[Abambo]

How do you create the PDF file? What happens when you scale the data a lot? Adobe uses screen optimization, so it's display is not always accurate. It tends to be accurate when you go to higher zoom values, or when you print the file. 

[Pierre_6.1]

I use one of the *.pc3 virtual plotter files that comes as part of AutoCAD, usually the "AutoCAD PDF (High-Quality Print).pc3" plotter file.  It doesn't matter which pc3 file I use, however: the results in Acrobat Pro are the same.  I also ensure that the "Plot Object Lineweights" option is selected in AutoCAD.  So to circle back to my original inquiry:  is there a way to control the settings in Acrobat Pro to adjust the screen optimization?

[Abambo]

Please share a PDF file with us. It can be a dummy file, but it should be clear, what thicknes what lines should have.

[Pierre_6.1]

In the attached file, the surface profile and the outline of the retaining wall should be twice as thick as the other outlines and details, and the crosshatching should be razor thin.  If you email yourself an attached copy of this file, this will become readily apparent.  Our clients usually use Acrobat Pro or Reader to view the files, so I hope to find some sort of resolution to this issue.

[Pierre_6.1]

Can I assume by the silence that there is no way around the Acrobat display settings?...