I was going to post the same question today.
I did the headgasket on my 82 Rabbit and I tightened the bolts (new) following the Haynes manual:
30 ft.lb - 40 Nm
44 ft.lb - 60 Nm
55 ft.lb - 75 Nm
Then with a breaker bar, I tightened an additional 1/2 turn.
I started the car, and started very well, I let idle until it reached the operating temperature.
I removed the valve cover, and start to torque the 1/4 turn, when I was doing the first bolt, it make a LOUD POP, and the breaker bar seemed to skip a little ( tought the bolt broke) but it didn't, then I said to myself, "That's it!"
I'm going to leave like that.
The engine start and runs very good, I didn't see any leaks so far, then my question is the same as yours