A late war loadout order looked like this:
http://www.uboatarchive.net/BDU/BDUOrder60.htm
Some of the 1941-1942 KTB's and shooting reports mention a load of G7e's and two G7a's.
Dönitz seemed to like his U-boats to get as close to the enemy as possible so I'd expect he would have had an interest on the types of the torpedoes used, preferring accuracy/sure destruction to long-range safety/inaccuracy.