http://fc3spro.com/TECH/MODS/EL/GAUGES/wtemp.htm
I run an electric fan through a Spal controller.
Mines is set to trigger on at 205F and trigger off at 190F.
Keep in mind that the stock Mazda thermostat opens at around 180F.
If you run a stock Mazda thermostat, there is no reason to run a controller below that temperature as you're just fighting the thermostat itself.
-Ted