This looks like a way forward certainly, excellent work! I'd love to have a go, but my knowledge/understanding of electronics is just about zero.
I think what will be needed for most of us to do this is a simplified set of instructions. For example, I personally have no idea how to connect to the Ibus, or where it's kept.
I guess you constructed the circuit by soldering the components to one of those perforated boards? Could you create a 'HowTo' containing a list of the required components and any reference numbers they may have? It would also need a simple circuit diagram representing the perfo board and what item is soldered where.
I once made a ciruit for an ultrasonic detector for bats using this sort of kit and it was pretty straight forward - and it worked! The wiring diagram was clear and simple and the instructions were written in everyday language without any technical jargon.
If you could eventually provide something along those lines, i'm sure there are lots of members keen to install a proper coolant thermometer. Many thanks for you valuable input.