Suggestion for my swimming routine

Great app, many thanks! One feature I think could have wider uses: for a given text/book allow the possibility to make custom length mp3 files. I swim with an underwater mp3 player onto which I have to copy audio files (normally lectures). The length of the audio file (about 30 minutes in my case) determines the length of my swim training. So it would be v useful for me to have the option of the app creating roughly 30 minute files (or eg between 30 and 40 minutes) from a given text. Ideally it would choose a good point to break the text. And insert a “End of part x” notice plus a break. Cheers, Peter