What is the best approach for could be true EXCEPT questions on LR?
I find my eyes moving from each answer choice to the stimulus and back again. The stimulus is so detail-oriented and chock full o' facts.
On the practical side, I suggest you circle the word "EXCEPT" and draw a line from it all the way down the left side of the answer choices. That way you notice the word "EXCEPT" each time you get to an answer choice.
On the deeper side, defer judgment on anything that looks possible as you look for what can't be true. You're looking for something that the stimulus disproves/makes impossible.
Some of these can definitely be tough!
I hope that helps.