Another drawback FSRs have, is that they easily split in half under sideways (shear) forces. They also only work under compression, and tear under tension. This is why you want to make sure that pressure can only go straight down onto the FSR (a delaminated FSR can be seen above). Depending upon how hard you expect to press on the sensor, this may not be an issue. But, if possible, have the actuator that presses against the sensor constrained to move only up and down. This can be accomplished with a small groove, or a cantilevered hinge, as shown below.