I have recorded in go pro at 1440 high with end product always intended to be 1080, done this so I can adjust horizon and use stabilisation methods in post production software, extra image prevents need to scale as much, uses storage but buy a bigger card and get the keeper image , try it
Kilrah is correct: the 4:3/16:9 setting applies only to stills.
I strongly recommend the 4:3 setting. When you switch to 16:9, the only difference is that the camera just omits the top and bottom pixels from the image. You don't want the camera doing that; you want to be doing that yourself in your photo editing software.