I wanted to start out the same thread... I am having the same questions

OK. Well Manhattan (they have ' OG stopwatch' that helps you with timing) says this:

"120 seconds per question for all question types but Sentence Correction.
90 seconds per question for Sentence Correction.

(Note that on the GMAT, Reading Comprehension questions will come in groups of 3 or 4. You should spend 3-4 minutes reading and understanding the passage, then about 60 seconds per question. This procedure results in 120 seconds per RC question, including the time for the passage.)"

I will try this approach now

What do you use to time yourself?

At Knewton, our policy on timing RC is as follows-

Spend 2-3 minutes on any passage- this includes both reading and making any notes you need to understand the structure and main ideas of the passage. A longer passage will take a bit longer, naturally.

Then spend 4-5 minutes on the set of questions (you can't know whether you'll get 3 or 4 questions beforehand, so this averages out to about 75-80 seconds per question)

This means spending 6-8 minutes on a passage in total.

Try these timing tips in practice:

-If you see a short passage (one-two paragraphs, 250-300 words or so), set a timer for 6 minutes and see if you can get through the passage and three questions in that time. If there are extra questions, use 75 seconds per question as a baseline for timing.
-With a long passage, (2-4 paragraphs, 350 words +) set a timer for 8 minutes and answer four questions. Again, use 80 seconds a question for any additional questions.

Best of luck! Remember, reading actively yet quickly always gives you more time to go back and find relevant details later!