We visited the lounge on a Saturday evening. First come, first serve, and we did not check in at the desk. We just took two open seats at the bar.
We also went for lunch on a Tuesday and ended up sitting in the restaurant, as I didn't realize the restaurant opened for lunch at 11 and the lounge at 12 and we arrived at 11. When we left a little after 12 there was barely anyone in the lounge.