Ok i've had a play with this.
All the settings were correct as per your post. The quality seems a lot better when printing from the View Port in paperspace. When I do a custom window and print from the model space I get the results as attached in the zip folder below:
NOTE: The drawings are a knock up to show the issue and not an actual drawing for issue.
I don't see any drawing attachments. Would you try and upload them again please?
I wanted to check back one last time to see if you can post the drawing files or did you resolve the problem?