Hi Don,
Then you are pretty well going to have to use AC bridge techniques, like the transformer ratio arm (aka coaxial bridge), and probably make it self balancing, else the "non-linearity" over range will drive you mad !

If you want to know a bit more, I can post a couple of outline schematics for the technique.

The self balancing bit is the tricky bit, but there is a lot of black art to making the transformers.

Steve