Unrejecting entire Aperture library & restoring ratings

An accidental keypress appears to have "rejected" all 55k (1.6TB!) photos in my library. (I think all of the photos were all selected and someone bumped the keyboard presumably pressing '9'...?) I'd like to restore the rejected photos to their previous ratings. Is this possible?

I've seen many threads on how to unreject photos—essentially by re-rating them— but the number of photos obviously precludes this approach. I find it hard to believe that a single keypress (when all photos are selected) could be so catastrophic. (I am past the window for undoing... I just noticed this; I'm not sure how long ago it happened.)

If it is not possible to restore the ratings in bulk, my (literal) backup plan is to restore the entire .aplibrary from Crashplan, but this will take 40+ days.

One other thought... I believe the Masters are still in place, just tagged as "rejected". Is it possible to restore only the database files (from Crashplan), then overwrite just those in the .aplibrary. Is this approach viable? Which files would I need? How significant are the risks of corruption with this approach?

Thanks for your help!

Randy