Guest wifi scheduling via iptables

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Let me start out by saying that my iptables knowledge is limited.

I am trying to mimic Parental Control Scheduling on the Guest Wifi. Reviewing iptables I was able to piece together the following.

iptables -A WGNPControls -i br1 -m time --timestart 07:30:00 --timestop 07:45:00 --weekdays Mon,Tue,Wed,Thu,Fri --kerneltz -m mac --mac-source xx:xx:xx:xx:xx:xx -j DROP
iptables -A WGNPControls -i br1 -m time --timestart 21:15:00 --timestop 21:30:00 --kerneltz -m mac --mac-source xx:xx:xx:xx:xx:xx -j DROP

Is this the correct syntax to disable internet between set times and dates based on mac address? If so I should be able to added it to firewall-start so it is added on reboot?

Your help is appreciated..