FSR linearization when using adc
You may not be able to do what you want.  When the sensor is just one leg of a resistor divider, then you get the maximum resolution when the sensor has the same resistance as the other resistor of the divider.  Such a setup can deal with the 0 to infinite range of the test resistance, but measurement resolution drops off with the ratio between the two resistors.

To decide whether the setup is good enough, you have to first decide what the resistance range of the sensor will be during intended operation.  Then you have to decide what resolution you want to measure the resistance with.

You want the fixed resistance of the divider to be such that it is the same ratio from either end of the range.  For example, let's say you care about resistances from 1.2 k&Omega; to 340 k&Omega;.  That's a ratio of 283.  The midpoint in ratio-space is the square root of that from either end.  That is 16.8.  The midpoint is then (1.2 k&Omega;)16.8 = 20.2 k&Omega;.  You should get the same thing by applying the midpoint ratio from the high end: (340 k&Omega;)/16.8 = 20.2 k&Omega;.

To find the worst case resolution, do the math.  Compute the voltage into the A/D for either extreme.  Then work backwards to see what resistance would yield one A/D count more to the middle.

Using the above example, you have a 20.2 k&Omega; pullup and the test resistor to ground.  At 1.2 k&Omega;, the output voltage of the divider is 0.0561 of the reference.  Let's say you are using a 12 bit A/D.  The A/D output will be 230.  You therefore have a resolution of 1 part in 230, or not quite 8 bits, at the ends of your range.

That's the resolution you can measure resistance at.  Now work that back to see what pressure delta that represents at both the low and high ends of the range.

If this isn't acceptable, then you have to do something different.  For example, you could use a higher resolution A/D, or a different topology altogether.