If you do go the route of using a HOT/COLD more modern non-thermostatic valve, folks have had good luck reducing the output flow of those valves by putting a ball valve from your local hardware store in line between the value and the fill flume. Otherwise the washer will overflow for several intervals during the fill sequence due to the larger (or sometimes non-existent) flow washer.
I've had luck using a relay to switch both sides of the valve on when the washer calls for WARM for washers that only have a WARM/HOT option via a thermostatic valve.
Looks like the early Unimatics have the temp switch feed back to the GREEN terminal on the timer when Warm is called for wash. You could wire in a relay on the GREEN lead that feeds the cold solenoid, and when it is active have it feed current to both sides of the water valve, rather than just the cold side. You have have to experiment with different methods but it shouldn't be too difficult to accomplish.
Ben
