Quadcopter PID

Hello everyone,

I'm making a quadcopter, using an arduino nano an mpu6050 and nrf radios. My question is has anyone used this PID library http://playground.arduino.cc/Code/PIDLibrary for a quadcopter? I'm currently tuning the Kp parameter and I've got no idea what range I should use. I've seen other codes and they use values between 0-1 however when I try that the new PWM values don't change very much so I've been using values like 3/4/5 and even hight but with no luck. The quadcopter doesn't stabilise. Has anyone got any ideas?

Thank you for your replies