lucy24 - 4:54 am on Dec 10, 2011 (gmt 0)
Where are you getting the pdfs? If you're using the Mac's built-in PDF generator, there is a HUGE difference in filesize between different browsers' output. It isn't a webkit issue; in the test* I ran, Chrome's PDF came out six times bigger than Safari's. Others are in between.
* This is fortuitous. I was recently yakking about a related issue with my father, and made a packet of PDFs from the same HTML file to experiment.