My hope is that I can get the db back to 1/10 and maybe we can, with Atlassian's help, somehow sync the lucene files back to the db. I don't think I will have any postgres data to work with beyond 1/10.
Does this still sound do-able with that kind of data gap?
I'm not sure how the incremental updates to the lucene indexes work with Jira. If they are parallel to writing to the DB maybe you can recover some info there; if they are trickled out asynchronously after writing to the DB by an index process that reads back the DB, then I'd expect there to be no additional info there.
Perhaps the best you can do is get Jira to run its integrity checker on the current data and fix whatever it tells you to fix. I think Atlassian will know best.