when i do bombinb runs, and i'm no expert, but hit, 80% of the time.... I usually climb to 10k if very heavy, or 15-20k if not so heavy (i.e. bombinb towns, or what not)....
light up inital approach, press f6, (bombing sight)
Press U enter calibraton mode)
Press Y hold, for x+2 where x = how ever long you feel is right
Realease Y
Press U, exit calibraton mode
Wait... Adjust as needed with stick, maybe add .salvo or .delay if i feel like it
trigger bombs...
press F3 if not in combat
check skys with views.. then Press 0 (default down view)... watch target for effect.... Eject if miss... chute... rince and repeat