The 5 hole sender mounting pattern is spaced so that it only clocks/fits one way. We see these gas gauge problem a lot. When it gets to the point of replacing with several units, and frustration sets in, and suggestions aplenty. It is time for a bench test of the gauge and sender together to calibrate or at least see what they do. Be sure the extreme up and down match full and empty depths. This bench test (or sender on the seat test) must be done or you will go broke and crazy. You will have no money to pay the co-pay for treatment. As I already said, when testing is done, then seal the float to be extra sure. I still want to know how it was determined floats were bad.
Possibly you have figured it out already or have decided to become less precise. Like your steering, handling, wipers, brakes, speedometer, oil pressure gauge, ammeter gauge, temp gauge.......
