I have a simple solution to this, at least if you want maximum compatibility with single layer dvd-r. I have done many projects close to this size and I simply have Encore write the project to the hard drive and then use DVDShrink (freeware) or Nero Recode (Included in Nero 7) to shrink it to fit on a 4.7gb DVD. Both work surprisingly well, especially since one is freeware and they were both created by the same developer (or so I have heard).