Regardless of the size of an sce, if it is used as a dependency then there will be no duplicate packages between it and sce's that are imported using it id as a dep. If you have a base.sce and use it as a dep for a desktop.sce, then any package dependencies needed by desktop.sce that are in base.sce will not be included in desktop.sce since they exist in base.sce.
That i understand, and that works just fine. My problem is that so far no matter how i try, multiple packages will still share quite a lot of low level system packages that compose undefined base set, that i have to figure out by trial and error.
So far that set entails coreutils, zlib1g, bzip2, util-linux, gcc-base, libc6-bin, e2fsprogs and i am not sure what else. I keep seeing packages duplicating those debs, and to minimize duplication i have to redo my bottom level sce's. Finding that common denominator is mostly done through experimentation.
I would just like to have something resembling a system set of debootstrap wrapped up in one sce, but i am not sure if that is defined as package set. That would greatly shrink other sce's i am deriving from it.