Fuel tank sending unit

I need one for my 68. My question is why should anyone have to monkey around bending a senders float arm and settling for a gauge that will not function the way it did from the factory and will suddenly drop like a rock and read somewhat correctly again when empty? There is no excuse why any of these companies couldn't have put the care into making a sender that would fit and function correctly for these cars.
I was hoping that these Australian senders would be the answer to this problem and function correctly. The original poster says they do. I sure hope if I shell out nearly $200 for one it will.
Weren't these guages for these Darts made by Stewart Warner for Chrysler? I'm not sure about the 60's but I believe they were in the late 1950's. I remember seeing that somewhere.