The info is on Davies Craig website- www.daviescraig.com.au
They make all the aftermarket thermo fans and fan clutch plates.
I remember reading that the idea of the pumps is to:
1. Replace existing pump. No more wasted engine power
2. Replace thermostat. Control the temp of the engine better
3. Run after engine shutdown. As you said, to cool the engine in a more reliable fashion.