I used a decade resistance bank which allowed me the test and calibrate much more than the service techs 3 position tester. That doesn't mean I could force or alter the aftermarkets linear sender to function like the OEM non-linear sender. What I did know.., all the gauges operate on the same 80-10 range. 78 ohms would begin to slightly warm the gauge winding but not enough to cause needle movement. 73 ohms would or should bring the needle to the lowest hash mark (on a fuel gauge that up to the E). Approx' 34 ohms is both 1/4 tank of fuel gauge and 180 degrees where thermostat would begin to open also. I don't recall how much oil pressure 34 ohms represents. I could go drag out my books but you may not have a oil gauge in a standard panel anyway.
I did read 3 ohms in one of the posts above which disturbs me. As low as 8 ohms can overheat the bimetal beam inside the gauge given enough time. Once that beam loses its original form (arrow straight at 68 degrees) it will remain bowed so the needle can't go all the way to its home position at switch off. If off there its off throughout its range/movement.