Disappearing Fuel Level

I've gotten all of the lights to work on the bench with a 12V 5A power supply connected directly to the individual pins and the gauge frame. What I didn't have was a resistor anywhere in the range the tank sender would provide (RIP RadioShack). I dont know or care about the other temp, oil press, or alt gauges as I have electronic transducers tied into my microsquirt. E85 isnt super popular in NC so a working fuel gauge would be great. I do need to clean/tighten the nut on the fuel gauge as I saw the effects of some corrosion when testing the dash lights. It seems like a certain amount of time wasted dealing with electrical stuff is required with these 40yr old cars.