Set up as described in Part 2 didn’t actually work as I found out the hard way after a power cut.
As per recommendations on http://forum.tinycorelinux.net/index.php?topic=4983.0, I have now tried the following:
Add to “/opt/bootlocal.sh”
crond -L /dev/null 2>&1
sudo crontab -e
*/30 * * * * filetool.sh -b > /home/tc/cron.log