Got the new sending unit installed this morning. As the tank is currently full, I won't be able to truly test it until I hit the road in Feb. What I can report is being full, it is showing the equivalent of just over 1/16 past full. It's been a couple of years since it worked right, but I seem to recall full used to be more spot on than that.
As long as it is accurate on the bottom end is what is really important. The new units from Centroid are micro-controller based and are not field-adjustable, but can be adjusted at the factory they say. These also have some logic in them they call "AutoCal Full" that uses "Full Detection" at each fill-up. Will see how that works over time....