Unless you've got special servos, they usually don't get much more than 70-80deg rotation unfortunately, despite having about 160deg mechanical rotation. From personal experience I couldn't increase travel using pwm parameters. My fix was to insert resisters (2.2k) into two wires inside the servo (basically gives the servo a false/reduced reading of its angle). that should give you plenty of travel distance without reducing torque, though it's a bit tedious to do.
Here's a (not very clear) picture of my servo with two resistors connected inside. There's some helpful youtube clips on it too