Although there doesn’t appear to be any straightforward way to run command tools or scripts only on Efficiency cores, there are ways and means.
Prior to 10.4, Mac OS X used cron, then scheduling became part of the job of launchd. Later Apple added a new subsystem, Duet Activity Scheduler, which continues to evolve.
Asymmetric Multiprocessing (AMP) can bring great economy in power and heat production. So why don’t we make better use of it on M1 Macs?
What are the penalties in real-world use for running your code on Icestorm cores, using around 10% of the power used by Firestorms?