You might also take a quick look at some of the various scripts people have written to do this automatically. Haven't tried them myself, so no idea if they work, but here are two I found:
https://www.mobileread.com/forums/sho...d.php?t=186102
https://www.mobileread.com/forums/sho...d.php?t=192581
Easiest is to probably back up your current database, run the script, see what happens
