I think the selection and challenge process you are speaking of is often unique to the case in court at the time. In the case I ended up on as a juror, our panel was selected within a week, if not just a few days. It was a very quick selection process. The only question we were asked was whether we had a bias towards mental illness and mental health, ironically, because it was an NCR case—not criminally responsible—so the defendant was offering a defence of mental illness to absolve him of the crime.
Patrick can probably speak to challenges and the like at length.