Hi stoneage,
what you have done is just "ripping" the content/getting rid of the copy protection… step two is re.compression; two tools on the market:
PopCorn by Roxio… a commercial product, esp. meant to work in combination with Toast
DVD2One by
http://www.dvd2one.com/ - highly recommended tool for 40€, with easy settings but also with some very smart extra functions (e.g. selecting single tracks, recombining multi-part dvds, selecting a "preferred" language etc) and, of course, you choose the final size, so to make a dl dvd fit on a single layered dvd
in many cases, choosing "main feature"/the main movie only, without making-ofs, games, whatever, makes the content smaller… you can do all that with DVD2One…