I always go for to cockpit....
You just have to time it right... I use 110 meters convergence... and alway get in close before I shoot... Usually I'm well within 100m when I pop someone...
With such a close range... deflection is not as important... maybe just a few feets... works like a charm... I most have killed a couple 1000s 109/190s online in the last 2 or 3 years... with a average gunnary of about 10%. All my burst are usually about 0.5 to 1 sec long... I never spray a target (well only when I'm out of 20s)...
Also when very close (read just a few meters) you have to offset your shots to account for wing mounted guns (I fly only the Spit). Its a blast to see a bandit break up just a few meters from you as you fly by him... Same for long distance shoots (read about 200m) usually aim for mid wing in order to hit the fuselage or wing root... but these are lower % shots and I mainly use short burst (303s or 50s only) to get a bandit to turn... getting them as close to the cockpit as possible tend to make them turn
Once he turns... go into a high yo-yo and kill him...