Something similar that I was working on except this is for voltage and oil pressure.
The dial is 1-5/8" to fit in the headlamp shell in place of the ampere meter. The pressure sensor is about the size of the switch. There are ten LEDs around the edge, red, yellow, the rest green. The three digits in the middle show voltage.
The problem that I had was the same as with the multi-colour oil pressure light to replace the switch light, too many people had different ideas on when each colour, or, in this case, what pressure, each LED indicated. The measurement of the voltage comes from comparing the power wires.to an internal reference.
I use micro USB cable for the pressure sensor because they are cheap, small and I do not have to make them up.
Oil temperature measurement usually comes from a Negative Temperature Coefficient (NTC) sensor. The question is where to put it. You could use a tee on and oil line but NTCs with two wires are usually fairly large compared to the single wire type and it flapping in the breeze will likely break the wires eventually. But with the single wire you need the other (threaded) side grounded. Unless it is an OIF the tank is typically mounted on rubber buffers which isolate it from the frame. An OIF has the problem with the centre stand hitting anything in the bottom plate.