When you loosen the Cam pulleys there is no key way so they are free to rotate, so there is no way to acurately set the timing in advance or Retard, as said above you dont need to set them this is done by the belt and tensoner once this is tensioned up the cam pulleys will be where ever they are, then you tighten the pully bolt. The timing itself has been set by your locking tools. The only thing to remember is you MUST loosen the pulleys, some people try belt changes without doing this and the VVT solenoid throws a fault, you have to get it all cock on to keep the VVT solenoid happy.