How to set advaced printing options when using "lpr" to print?

On ubuntu Hardy 8.04, some PDF files have printing issues - they take forever to print, all this while evince (the PDF reader) uses 100% CPU. After that, the actual print comes out very blurry and unreadable.

I usually use pdf2ps to convert them to a postscript file that prints without any issues, but that's not always the case.

In those cases when the ps come garbled, I use lpr to send the pdf directly to the printer - the problem is that I don't know how to set 2 sided printing with lpr.

I print enough PDFs for these edge cases to matter, and having this command line option will also allow me to use a script I once wrote that takes a URL as input and sends it to the printer.

Does anyone here know how to set this 2 sided printing option from the command line? man lpr shows that it has a -o=options flag, but I cannot find the relevant option for this.