FOV (Battlefornt reports vertical I believe) is how much of the world you get to see on screen at any one time. If you're playing ona monitor, or a large screen, or basiclaly any time your display takes up a significant portion fo your field of view, you want this to be higher than the console "standard" of 65-70 (that's equuivalent to 50-55 on the battlefront scale). That's just WAY too narrow.
For my 27" 16:9 monitor at about 2 feet distance, I prefer 85-100 (about 60-70 on the battlefront scale) depending on the game, but YMMV. Experiment. For a 21:9 ultra wide monitor or a multi monitor setup, or a large TV you're sitting close to, FOV should be set even higher. And yes, with a higher FOV, there will be a hit in performance, as you are rendering more objects per frame.
Scaling is basiclaly down or upsampling, depending on whether you go over 100% or below. So upping it to 200% and being at 1920x1080, you are doubling the resolution and then downscaling to 1080p. That should give your IQ a big boost. But the performance hit cna be pretty big.
