Thanks, Werner.

FWIW, for the CD-size 2 Gb LiveUSB, with no re-mastering, just Synaptic:

Size of free in /home/knoppix at first............................................. .....................598.2 Mb
Size of free in /home/knoppix after .addition. of IceWeasel using Synaptic...590.8 Mb
Size of free in /Home/knoppix after 'deletion' of Chromium. using Synaptic..555.7 Mb
Size of free in /Home/knoppix after .addition, of Ad Block + and Subscr........505.6 Mb

Chromium, in this case, remains a part of the KNOPPIX compressed file.
It would be a LOT cheaper in Mbs just to keep the Chromium if you can't re-master.
Moreover, re-installing Chromium at this point doesn't seem to be an option using
...Synaptic because of 'uninstallable' broken dependencies