First Gas Tank swap - What do I need to know?

In my Duster project, the same leaky gas tank came up. I soldered the holes, used KBS tank coating to seal in the holes and give it an impervious coating. Then purchased a new sending unit. In hind sight, I should have just purchased a new tank like you did. It would have saved me lots of time. And do save the old lock ring. The new one didn't lock as well as the old one did and I even reused it.