The benefit of the coolbot is not having to do anything. The con is that it's $200 more than a ranco. One way to fool the stock probe is to tuck it around the side of the unit so that it's exposed to the unconditioned space but that only works if your ambient temp is above the lowest stock setpoint of 60F.
Another DIY version of coolbot would be to set your stock thermo to 60F and keep it plugged in to constant power. Run a ranco and have the controlled output hooked to a 1K ohm, 25 watt resistor that you couple to the AC's stock probe. It provides the same kind of control you're looking for by applying heat when cooling is required. Obviously wrapping insulation around the resistor and stock probe will help.
Another DIY version of coolbot would be to set your stock thermo to 60F and keep it plugged in to constant power. Run a ranco and have the controlled output hooked to a 1K ohm, 25 watt resistor that you couple to the AC's stock probe. It provides the same kind of control you're looking for by applying heat when cooling is required. Obviously wrapping insulation around the resistor and stock probe will help.