How are you updating your set each time Alex? If you just join the latest torrent and point the download at the existing set you don't need to verify anything, just let it download the difference, and then seed away.
I say verify, I mean check - uTorrent looks for what's already downloaded so I start >90%. For some reason (probably the size of the thing and number of files, combined with a USB External HDD) this takes ages to do.