iptables.tcz.info includes the line.
sudo /usr/local/sbin/basic-firewall
sudo is not needed. You can just use:
/usr/local/sbin/basic-firewall
I suggest writing:
To start the basic firewall each time Tiny Core is started, add
/usr/local/sbin/basic-firewall
to /opt/bootlocal.sh.
This makes it easy to understand for new users.