Summing this stuff up: my new He-111's just like my Ju-88's before... I get blasted by 5inch every time. 
My guess is fire the torpedoes just before the auto ack machine guns start taking us apart! No chance with 5 inchers over there!
Coming in under 200mph, under 200ft:
Only once of a couple of tries did even one of my planes of a 3-set survive to where the auto ack guns began firing at me! 
Dropped both, turned hard, got killed seconds later! Boo! 
 Dam the 5 inch guns! Why not just have these at bases? Would definitely fix any vulching probems!
How the heck to get the 'torpedo a ship' achievement! 
Yeah I know, I need to go to the training arena and get certified! Still, take 5inch out please!