We find ourselves in a somewhat similar boat to Qamarudeen. Is there any hope of maybe forcing Moodle Mobile to check the file system instead of the Database in order to avoid downloading the large content? If all we had to download on each iPad would be the additional data, like the attempts information you mentioned, it would significantly help our situation as I assume the download size would be minuscule in comparison.
We're happy to test some approaches on our end and report our findings if you could perhaps point us in the right direction.
Thank you for your help Dani!