How I solved my 1974 Duster fuel gauge problem.

You really need to set the mid points on the meter match on an A body due to the spare tire notch in the tank. Setting only the high and low points is not going to be accurate.
I installed the A-100 sending unit in my dart and its mostly accurate. It has the correct tapered winding like above.
Dodge 64-70 A100 Truck/Van, 67-70 A108 Van Fuel Sending Unit 5/16", Gas Sender | eBay