I would be careful with that approach - they can and do push the “curtain” forward if they want to sell more Go seats and the flight is getting full. It’s happened to me that there were, say, 6 rows of Plus, with the flight relatively empty when booking a month or so out. At the time of booking, I chose an aisle seat in row 5, and then when checking in, suddenly noticed that they had pushed the divider to row 3 and placed me in a middle seat. Fortunately I was able to get the last window seat.
Not really sure what the lesson here is, other than making sure to check the seat reservation once in a while...