What is the maximum force that a FSR sensor can detect?
Not sure
Yes, since its conductivity (1/R) varies with applied force to distinguish smaller forces you need larger voltages.
That seems to be what the datasheet is saying, subject to sensible mounting.
Drive it from a current source fixed to (say) 1ma, but with plenty of "headroom". Then measure the voltage across it.


(The suggested circuit looks like a transimpedance amplifier?)