I had a file for 11-story building, 3D, BIM-friendly, with all the IFC stuff, and
without the furniture, plants, people, etc. the file was 380 MB - YouSendIt came in very handy
To reduce the file size I changed resolution from 300 to 150, turned off quartz imaging, simplified my GL options, and yes, final quality renderings and IFC conversions are better done during lunch or overnight...