I was able to try one of the two circuits and got it to work as shown in the attached sketch. The second circuit I was not able to test as I do not have the second transducer. I did build the circuit in LTspice and it works. However, the control is triggering at about 0.6 V and the control low is rated as <0.9 V. It could, in theory, not open or close unpredictably. The measured low is 0.0 V but this is without anything else connected to the controller.
Anyone's input would be appreciated...