Got the Spit film now. As Slapshot says, you MUST lose the tanks in fights like this. You may be able to fight P-47s with the tanks, but not Spitfires and Lavochkins.
I normally take 50% internal plus the drop tanks, and drop them no later than the second pass if I'm engaged with a plane such as a Spitfire or a Lavochkin. I only keep my tanks if I have EVERY advantage and am reasonably certain of a relatively easy kill, and even then only if I am a long way from home. If I am close to home, I'll drop them anyway. I'll also drop them if there is another enemy plane close enough to be a real threat.
Again, you must get more aggressive and move more quickly to get the kill. The P-38 is a large target, and you simply cannot afford to hang around and risk the enemy even getting a passing low percentage shot at you. Note that in both films, both planes took major control surfaces from your plane with relatively low percentage shots late in the fight. This is VERY common with the P-38 unless you have a large advantage and are simply playing with your food. The P-38 has plenty of ammo, and is a stable and accurate gun platform, don't hesitate to take good deflction shots if you have the chance.
You are getting closer to turning the corner, you are not that far off. The P-38 really takes a lot of time to master, I still have not mastered it, I'm only decent. You are correct that it does require you to fight very strictly to its advantages, and is flown like no other plane.
