Actually, figuring out how to convert and optimize PDF files for older machines would be quite useful since a lot of people face these issues to varying degrees. For example, many newer 68k Macs choke on PDF files because they can only run Acrobat 3. Even computers that can run more recent versions of the Acrobat Reader (or third party utilities) usually choke on the performance front. So please let us know if you discover anything useful. Even if it is an intermediate step to your final goal.