Richard. There is a wealth of information on the subjects you mention in this forum and others. I have always found it best to do my own research and post a question when I have a better understanding of what my needs are. To answer your questions. "It all depends".
Uh...2-6 hours to shoot a wedding? What kind of weddings are you working?
I generally show up 2 hours before the bride and groom arrive (if we're not with them before hand) and we don't leave until they pull away in a limo (or their car). I've had 10-12 hour days be the norm.
2-8 hours of editing? I put it AT LEAST 40 hours of editing to offer a 75 minute finished film. That does not include the extras that I put on the 2-disc set.
If you're not busting your rear to capture every aspect and detail, then editing a final film in a movie-like fashion, then don't bother.