In Tim’s original there was a mechanism that would prevent enabling duplicated blocklists which doesn’t seem to be incorporated in this version. (It is the " ‘disable’ => ‘BOGON’ }, " line in the BOGON_FULL category of the sources list).
My firewall is set up to protect my SMTP port and I have 2 additional blocklists (Banish and
Local) but I find that different blocklists catch offenders on a day to day basis and currently LOCATIONBLOCK is catching the majority of the unwanted SMTP port probes.
This a screenshot taken yesterday showing my blocklist hits for yesterday. (Note I am still running Tim’s original version on my firewall)