Regarding gunnery: you need to lead quite a lot. A lot more than you might expect; give it a try in some turn fights against AI and see what I mean.
Also, it's a preference, but some people including myself do not bother using the gyro sight and just flick it back to fixed mode. You can see where the bullets go; that's why they're called tracers. The gyro is a bit to much fiddling for me in a heated fight anyway, but some people like it. As I said, it's a preference and in a thread like this, you will get a lot of valuable, but different opinions.