Save yourself a headache by requesting final ready copy. As the designer, it's your job to make the text fit properly within the design. If you keep offering text rewrites as a design draft, you'll never finish the project. Copywriters don't need to see and approve the layout. That's where the Art and Creative Director's job comes into place.
I make ALL my clients provide final ready copy. No exceptions!
If you need to have them approve the space for their copy, using greeking from the website: https://www.lipsum.com/ as a placeholder for the text.