Also, if you use NSIS and its built-in compression, you can probably distribute the lib/ directory as a set of files instead of a zip. This will save loading time for modules, allow easier installation of modules, and will obviate LibZip (and the 111K it uses when uncompressed). Also, the tinyperl you're shipping doesn't seem to be UPX'd. Your version is 16KB; the UPX'd version is 3.5KB. Finally, UPX'ing all the files in the auto directory of lib.zip will save you a good amount of space.
Good luck!
Bill