You cannot get preferred seats at OLCI for free anymore. They will be available at OLCI but for the same price I believe. You are better off paying for one now instead of waiting, as you will have more seat options. I have yet to fly on the new 400 seat configuration, just the old 2 cabin, and the 777HD. Row 18 has always been great on the 2 class, and the HD, but I have no idea on the 400 seat.