During all of my gaming either in single missions or campaign, I'm using far too many torpedoes.

I had something going a couple of week's ago where id gotten lucky with some small tramp steamers and had sunk them using 1 torpedo.
Now it's taking me two to sink them and three or four to kill an medium cargo. (using GWX3

)
Can people give me some tips on the ideal situation for torpedoes, where to aim impact pistol types and also the best depths for magnetic ones.
I'VE LOST MY TOUCH!
