Added in two more tunables:
Priority of the mover process itself (Normal, Low, Very Low) and
I/O priority of the process (Normal, Low, and Idle)
Setting these *may* help with the odd user where the mover process interferes with the normal operation of the GUI / other apps. Note that if your system pauses all I/O streams if/when a disk is required to spin up that these tunables will not help out all (In which case, do what I did -> adjust Kodi's (eg) caching settings)