We typically plot everything to PDF. Most of the plots files are in the 1-2 MB range but we have a couple sheets that end up being in the 10-20 MB range. We combine the sheets into a book using Adobe Acrobat Pro. The total file size for the books range 30-60 MB.
This makes emailing files a pain. So we have to use a wetransfer or an FTP download to get the files to clients or local jurisdictions.
We have tried all the options in Adobe to get the files smaller, but they never seems to work.
If you are using the PDF compression and optimization tools to their full potential, then there is not a whole lot more you can do on the file size end of things. We just FTP the files and email links. We have a signature in each users Outlook client that is preset so the user just selects that signature and then just copy and pastes the filename at the end and hits enter and Outlook creates the hyperlink to the file automatically which speeds things up a bit. Depending on the end recipient, this is usually the easiest option. No need for them to have some account they may not have or run into some other usage barrier they don't understand. We make sure to use simple file names using only alpha-numeric characters and dashes for the files being FTPed to avoid filename issues with the links. We test the links before sending to make sure we don't have an invalid character or a typo before sending the email.
We use Dropbox and have also previously used Sendspace. I'm sure if you do a web search there will be dozens of FTP sites that allow you to upload the drawings and just email download links to recipients.