LRF and PDF
I have just recently started offering the Sony format, PDF for Sony and LRF for Sony. You can't convert and strip a regular PDF file for the Sony. The PDF for Sony is a different formatting procedure.
I also learned that the PDF for Sony is fine for people with good eyes, but difficult to enlarge the font. Now we have made the font larger, and my tester said she could read it fine. But we also offer the LRF for the Sony which is the correct file extension for the Sony reader.