ghero, nice compilation and good idea (from a knowledge point of view).
Have you try to pass the first epub (part 01) through epubcheck (
http://code.google.com/p/epubcheck/)? It shows some errors in the content.opf file. Without them, it is quite possible that this file would load faster and could be better handled within various systems.
Just curious: would not it be easier (for the reader at least) to gather the articles, let say, from general topics to more specific one?
Have a nice day and thanks for sharing.