Making better use of Idle time / non-full-workloads

Hi!
Yes I am trying to do this with Redshift. The Slave starts a commandline app, that I manually set to the lowest priority in the taskmanager. Though since this commandline is restarted on every new job,I have to reset the priority again. I am also not sure if the taskmanager priority setting has any effect on GPU priority, or if it is just to set the cpu priority on Win10?