Marking the nut in relation to the yoke does absolutely nothing. When doing a re-gear, the difference between 160 and 200 is barely noticeable. I've tried just out of curiosity to mark and then torque to see how close it is and it's not an effective method.
You are correct with the torque spec 160-200. Now the question is, are you dealing with a crush sleeve or a shim pack? if you're dealing with a crush sleeve, you'll need a new one. Then you'll need to get to 16-20 in/lbs rotating torque after the sleeve begins to crush. It takes a LOT sometimes to get a sleeve to crush and other times hardly anything. I've broken a 1/2" ratchet trying to get a sleeve to crush before. Once it does start to crush, make VERY MINUTE adjustments until you get to the 16-20 spec. It doesn't take much at all to over crush a sleeve and have to replace it again.