That's cool! Are you going to check the sending unit calibration before final install? Make sure you have a good ground to the sending unit as well. I used a short length of copper wire and 2 hose clamps to allow continuity between the metal fuel lines and a chassis ground somewhat similar in effect to the factory ground strap which I don't have.
I had the tank out and flipped it upside down to check for how the float arm adjustment was. I had to bend the arm a bit to get mine right at full and empty. My gauge still shows full and slowly drops, but after I get down below 1/2 tank, it drops significantly faster. Not sure if its more than just the way the sender is wired versus when the tank was upside down the float was higher up than the fuel capacity of the tank lifts it.
I have a similar trick with grounding them. But on this particular sending unit it's in a 74 Ramcharger with a 36 Gallon tank, so it uses a stud that a dedicated grounding wire attaches to. I checked the OHM's on it, and documented best I could what ohm's the rang would read from F to E across 6 positions so if I ever decide to put a meter match in it, I should be able to get it close.
I ran the truck until it would stumble going around corners and still have 4 gallon's of fuel in it and luckily the float bottoms out at about that point.
