Good question, Wayne.
I haven't done it between M7 and M8 versions of Deluge, but I've done it between Mepis 7 and Arch.
All you need to do is tell the M8 Deluge what directories to use for "Finished Downloads" and "Scan." Just pick the same directories as you did in the M7 installation of Deluge.
Since Deluge [I'm pretty sure] moves the .torrent file from the "Scan" directory to a "loaded" subdirectory, you need to drag those .torrent files back into the "scan" directory. Or: manually load them each through the Deluge Menu. That is probably the safer course.
If a person hasn't got Deluge set up with a "scan" directory, nor set up to save the loaded .torrent control files, s/he would need to DL that .torrent control file all over again to get the seeding started. Deluge should only need to run a file check to see that the ISO in your "Finished Downloads" directory is indeed the full ISO, and should then start you seeding.
This scheme of course depends on a person using the SilverBear Recommended Practice of having separate partitions for your data and a dedicated partition for downloads.http://sblinux.org/pages/symlink-home.htmlIf a person just dumps all kinds of data into his/her /home/user/ directory, then whatever partition those downloads are on would need to be mounted first in the new OS, before the above directions would be effective --or even possible.
If there are any problems, please post back.