automatic full save

This might be possible with a script, but it will require installing it in a local folder on the computer, and it will only work for the current viewed file.

Also, do you want it to save the file to its current location (ie. overwrite it each time)? And how often should it be saved?

If I understand coorectly, the Adobe Acrobat integration with Dropbox, should allow you to adjust the "Save Settings" to whatever interval in minutes you desire Acrobat to perform the automatic save.  And yes it does saves to a temporary files, however, according to both Adobe Acrobat and Dropbox guidance,  their integration suggests that changes to these files are automatically updated.

In other words, assuming that you've already saved these PDFs in your Dropbox cloudspace, you should be able to open them from Dropbox directly in Acrobat, and even perform edits on such files while you're offline. 

For this to work, I am also under the impression that you must be connected to the Internet and signed in to your Dropbox. otherwise the files will be saved automatically to temp folder in your desktop computer.

Here are two links that basically imply that this workflow is possible:

• https://www.dropbox.com/apps/adobe_acrobat
• https://www.dropbox.com/app-integrations/adobe

NOTE: I may be wrong though.  🙂