Hmm, someone is welcome to check my math but if it took you 5 hours to go from 3 gigs to 5 gigs, that is 1GB per 2.5 hours, with 10TB roughly to go you should be done in about 5 to 6 months... But I like the idea, if I had the space and the bandwidth (I'm not -that- patient) I'm sick enough to do it too...
I'd rather have the PDF's then the epubs for archiving, you can always reOCR the PDF's or use them as visual reference for correcting an epub whereas with the epub you are stuck with the original OCR...
-MJ