Can I measure large force using series FSR?
Instead of using a force sensitive resistor, use a load cell. This is a 4-wire device with a resistor bridge; the resistance between pairs of wires changes slightly when weight is applied. They're available in a wide range of weight ratings, from those suitable for weighing out individual SMD components, right up to those used to weigh trucks.

You'll need an instrumentation amplifier to get useful measurements out of it; a common choice is the INA125.