OK, here is the solution…
In directory /etc there is a file standby.conf. Edit that and change the line standby_time=10 to whatever number of minutes is needed.
The file minitorio.sh is actually located in /usr/local/sbin (not bin). It is pretty well-written and commented, so it is not difficult to follow. I did not find the SLEEPMIN parameter referenced in the original link I posted, but that did point me to standby.conf.
