It's a little-known trick, but you can compress PDFs in OSX without using a third-party tool, or Automator. In the print dialog box, choose ColorSync from the Copies & Pages drop down menu and select Reduce File Size from the Quartz menu. This standard Quartz filter doesn't do much to reduce file size in my experience, but additional filters can be made using the ColorSync utility, which can be accessed directly by selecting Add Filters... from the Quartz dialog box. Making the filter do what you want is a trial and error process, but it can be done. And once it's done, the filter is accessible right in the Print dialog box.