I will be flying AC 830/831 return flight YVR-LHR soon, which are both 763s

I will be in economy, and would like to have a good view of a movie screen.

I'm short, so the main screen is useless, no matter where I sit.

I like the window seat, so those small drop down screen are fine....if you are in the right row.

Is anyone familiar with which rows those drop down screens are located? I would like to know for selecting my seat.