I ordered a few prototype circuit boards for my design. What I have come up with are adjustments (trim pots) to calibrate the gauge and tank sender. Things may change after testing and software development. I have two spare fuel gauges for bench testing and of course the one in my car. I however have the Zilla sender in my car.

I'm planning on one adjustment to set the full scale of the gauge. This calibrates the gauge tolerance it self. A second adjustment calibrates the gauge empty reading. A third adjustment calibrates the sensor full value. A fourth adjustment calibrates the sensor empty adjustment. I added another adjustment which is not assigned yet for it's use. My plan is to have the FUEL light turn on at 1/8 tank level. Not sure if I should have that low fuel light flash or just stay on.

Of course the software will "filter" the gauge reading to prevent fuel slosh from moving the reading.

I have not even started the software yet but will have to get that going so when my boards come in I can start testing.