Do they have one with a thread-in temp sensor? They are much more accurate than the push-in radiator probes.
Derale uses a sensor that is threaded for a 6-32 screw. The actual sensor has a short 6-32 stud. The radiator "probe tip" is nothing but a piece of copper or brass with a female 6-32.
This won't be for everyone, but I bought a pipe plug that fits the unused trans cooler port on my radiator. I drilled and tapped it for 6-32. That became my cold tank temp sensor.
I made my own water flow sensor out of brass rod, an old hose barb male that fits the water port in my manifold, and some Teflon rod. I use this to sense the water outlet temp to control my water pump. The AC override, if a resistor is used, can set the slow speed to anything desired. This will, however, require some creative wiring tying the resistor back to switched 12V.....or a relay and the resistor strapped to 12V at the controller 12V line. Water in the block has to circulate slowly during warmup to prevent hot spotting, so I set the resistor value to just barely circulate water.
I actually run my cooling fan the same way, slow at cold. I do this to "push" air into the engine compartment so my intercooler heat exchanger (a VW radiator) does not heat soak from engine or engine radiator heat.
This keeps my intercooler at 100F or less (just a few degrees over ambient outside air) even when the radiator is not hot enough to run the fan, like in staging.
My system is a little nonorthodox, being customized for an electric water pump electric fan intercooled turbo car.
My home made dash has a battery voltage monitor that kills power via relays when battery gets below a safe level. This way I can leave my key on accessory to cool down. If I forget no big deal, systems power down on low battery and will not reset until the key is cycled.
I could integrate all of this into a real dual channel PWM controller. I just did a bump box using a PWM chip that would work. My next project, however, is a portable ignition simulator to test my friend's NOS car by simulating a running engine without actually running the engine. Then my buddy will quit borrowing my expensive bench test equipment to check his nitrous car.
If I did a fan controller I would do everything in one package, including low battery shut off during cool down periods. I'd also use a standard NTC thermistor comparable with a GM or Ford sensor that could move anywhere.