Truely speaking, u wont find anyone outside using torque wrench here (very rare). So just simply tight until its fully tight. Don't over do it as its not needed because engine head screws are pretty long and strong, it wont blow out easily.
But if u over do it, then u might have difficulty in sourcing one.
i have gt new fuel pump installed in the car when the mechanic said it got to be changed.\
still feel that the problem remains.
still feel that car is going to switch off on its own.