Found an interesting entry in the Notes/Domino 8 forum where a user called Rupert Clayton posted a method to

    * enable LZ1 compression
    * enable document data compression
    * enable design compression

all with one single compact command "load compact -ZU -n -v -C mail".  It is documented for 8.5 but works in 8.0.2 as well although I cannot find it in the admin help or the release notes.