The first is to buy a wall mount with enough downward tilt to give you a more perpendicular view of the screen. Even better is a mount that will drop the TV down closer to your eye level (make sur ...
And no, it has not moved or sagged away from the wall after the first 10 days. Nor do I think it will. Before I hung the TV, I pulled hard down on the mounts to see if there was any give.