Mike,
mdsconfig is just an interactive tool to quickly access various Check Point commands.
Your interest is in option 6 - Administrators which simply executes mdsquerydb.
Example:
mdsquerydb Administrators
Addtional queries to collect the admin type can be configured within $MDSDIR/conf/queries.conf
So a simple One-liner added as cron job via GAiA's built-in job scheduler would easily address your needs to send you the list as a mail.
mdsquerydb Administrators | $FWDIR/bin/sendmail -s 'Multi-Domain Super Users' -t MAILSERVER -f SENDER_EMAIL_ADDRESS RECEIVER_EMAIL_ADDRESS;
In order to run a python ($FWDIR/Python/bin/python) script you would first need to whitelist it within /etc/fw/conf/whitelist to be able to run it.