I fly 17s a lot (and get my share of fighter jocks with the bomber guns).
The fighter attacks generally break down into 3 categories.
1. The 6-lemmings. Guys will crawl up your dead 6 in B17s thinking they can outgun you. These guys may get a drone, but usually get a rude awakening at about 800 out. These are pretty stable to shoot at so I will usually go slightly off center and try to saw off a wing. 6 or 12 .50 cals converging on a wing usually makes that happen pretty quickly. If a guy is coming up my six in a perk ride (a tempest, or me-262) - I aim for the canopy and try for a pilot wound / kill. Even if they get a drone on that first pass, if they are wounded they are done.
2. The hi-lo attacks. The guys that have learned the lesson that you don't crawl up the tail of a pack of B17s will try diving down from on top or you, or zooming up from directly underneath. These attacks are more dangerous, but if you learn to jump from top turret to tail or ball turret quickly you can give them a hail of bullets. Guys coming down from the top will usually blow by the tail and attack from underneath - usually jump to the ball turret quickly and give them a burst there, and sometimes you will see them zoom out in front of you on the climb so you can get good shots in if you jump to the chin turret quickly. The low zooming attacker usually will end up on your tail - not many of them will have enough E to zoom by and come at you from the top. You can give them a burst with the ball turret and then jump to the tail guns for most of those guys.
3. The slashing attacks. These are the most dangerous guys. They have learned the lessons from #1 and #2, and will position themselves about 2K out, high on your wing and then come at you with a fast slashing attack. First, learn to lead these guys by a lot and just get hits on them - this type of attack usually becomes a war of attrition as not too many fighters can put that much lead on you in the quick pass these guys make. Also, as they are slashing across your formation, they tend to hit the drones first. Learn to step on the rudder while you are in the gun turrets so that you can turn and put more guns on the target - just a light step on the rudder, drops your wing enough to get the extra guns into play. I usually aim center mass at these guys and go for engine hits.
Use your F3 view a lot to keep situational awareness. Learn to control your buffs from the gun turret with your rudder so that you can take evasive action. I like to make turns that either put my tailguns toward the enemy, or just frustrate them a lot while they are trying to line up for hi-lo or slashing attacks. A lot of fighter jocks don't have patience, so if you make a few turns while they are trying to line up they will just dive on in on your tailguns and have a go. I don't spare the ammo - you have plenty, and nothing makes a fighter jock not want to stay close to you like a hail of tracers.
<S> and I hope to see you bombing your enemies into tiny bits.