Might be easier if you use the WiiChuck library: Arduino Playground - WiiChuckClass
For ESC control you would typically use the standard Servo library. The servo.writeMicroseconds() will give you better resolution (range is about 1000 to 2000 microsecond pulse width). If you are talking "PWM" and "6%" then you probably don't understand how hobby servos are controlled. That might be a good topic of research.