My naive thought would be to run your files through a batch PDF
compressor, something along the lines of:

http://www.cvisiontech.com/products/general/pdfcompressor.html

If the files are still too large, PDF splitters exist, giving folks
the option of downloading a page/ section at a time.

Best of luck,

Cab Vinton, Director
Sanbornton Public Library
Sanbornton, NH

"Politeness and consideration for others is like investing pennies and
getting dollars back." Thomas Sowell