Excuse my ignorance, but I really couldn't find a clear answer on STG.
Are you also seeding a show while you download it, or do you have to complete the show first?
All I can say is good luck Zeni. Bit Torrent sounds like a good idea but I haven't had any luck myself.
To answer your question though, yes you should be sharing as soon as you've got some of it.. the whole idea is to get bits of things from a bunch of different people rather than the whole thing from one source.
Previously I've given up on them about 5 times, and most recently I waited patiently for 3 days for one to finish. It was just about done and got stuck at 99% because I guess no 'seed' with the whole thing was available. So you can end up with multiple people sharing incomplete files.
I've uninstalled it.
So far, I've downloaded one full show, and will have a second show done by morning.
I have, however, made sure via the Tracker page that the shows I am downloading are being actively traded, so I haven't faced the frustration of incomplete shows. Perhaps that's something you could do, DF. I get the impression that this is something you have to stay on top of.