I usually do main movie only to try to keep compression to the minimum.I also cut out some beginning and ending credits.
Unless that original copy has a lot of bonus features on it,then I will compress entire disc.Main movie only is quicker to backup and quality will be near identical.100% according to dvd shrinks compression tab is what I shoot for.
Re-authoring removes the menu function so when you insert that backup into your stand alone,no more trying to find the remote.It will auto-play which is a very nice feature to some members.
Ac3 5.1-ch English is the only sound stream I use.I untick the rest,and untick subpictures.
Now on those larger DVD-9 movies like lord of the rings trilogy,I will use dvd shrinks adaptive error compensation enhancement like max smoothness. This will definitely slow you down,but gives you a great quality backup.
I use Shrink to analyze the disc for audio streams, extras, and required compression. Shrink is also a good way to check out what different angles in the movie are for.
Well, we talk alot about my childhood and he shows me these funny pictures... Oh, you mean DvdShrink? If the special features look interesting I'll keep those and I always get rid of the unwanted subtitles (gotta keep the english ones though!). I always use custom compression when needed to keep the main movie quality high. Great tool!