Found a link and it actually gives a great view of the gap described behind Row 51. Bad news for the OP is that the gap behind Row 65 is not at all similar.
My first thoughts on seeing Row 51 however was not that it would recline more (I thought that would be limited by the seat mechanism) but that people walking behind me would grab the headrest on the way past.
https://www.google.com/maps/@25.2428...7i13312!8i6656