I think it doesn't help to know which package is on which CD, because there might be dependencies to packages on other CD's, right ?
That's true, but if I need a package which has only a couple of dependencies I could be able to see in which CDs they are (and so on). Anyway, I'm going to donwload cds 1,2,3,4. I will donload later any other thing I could be interested in...
Any answer for question number 2? (Where can I download the non-US variant of the "testing" distribution (using jigdo or fetching the whole CD)?)