OK, I think I'm making some progress My DVD structure has four parts: Menus, Main Movie, Extras, and Unreferenced Material. When I reduced the size of the Extras, I finally noticed that all the gain in size was going to Menus and none to the Main Movie. By setting Menus as well as Extras to custom ratio and leaving only the Main Menu on automatic compression I was finally able to reduce the size of the Menus and Extras and have the gain go to the Main Movie. Thanks for your feedback.
If you leave menus and main movie on automatic, you should still decrease the compression in both the menus and main movie, although it won't be by the same amount. DVD shrink tries to keep the compression to about the same percentage for all parts if you use automatic. But I always opt to have less compression in the main movie than in the menus and extras as you said. I think you're on the right track.
