of all the factors (gunnery, ACM, SA, E-management, ground straffing, bomber killing,etc,etc) i find fighter-fighter gunnery the easiest

sorry.
that straight 6 shot from D400 is really easy I find.
leads, snaps and deflections only slightly tougher.
from any possition under 500yrds i can shoot any fighter down using no more than 10-20 cannon rounds, maybe between 100-150 50cals. thats including the missed rounds.
saying this my accuracy is still usually only around 9%, but i think thats because flying the spit i waste many 303s that dont hit while the few cannon rounds do the damage.
funny that some of us find different actions harder/easier.
Redd told me to try turning off my tracers the other day when i was having trouble hitting with a 109F(i used no tracers in AH1 but turned them on in AH2 again for films)
he was right, the tracers just get in the way.
its not about giving the game away to the plane infront, more about obstructing your view on target, escpecially with planes using 6+ different guns.
try no tracers, see if it helps.