fuel sender question

[chimp koose]

OK guys , I am about to finish up my fuel tank and I have bought a 12V fuel level sender that I hope to use with my 53 ford truck guage set . They are 6 volt converted to 12 with some type of resistor .  How do I measure the guage inputs and sender inputs and make them work together ? When full volts are given , the guage reads past full . When the sender is supposed to read full it has its highest power reading . At least I know the guage and sender both are at their highest at a full reading . Now what ? Our electricity teacher may be doing this for me but I would like to give him some Ideas as to what people have done that works . I am actually planning on setting the sender in the tank to read empty with at least a gallon left . I have ended too many trips with a gas guage pointing due east !