I agree with Fitzcarraldo, A Convoy Training mission would be great.
I use the "Dick O'Kane Fleet Boat" mission, for practicing torpedo attacks and methods, and a night convoy scenario would be helpful for testing tactics.
Currently in campaign, I'll make a quick save when I detect a convoy, and replay it different ways.
I find I have pretty good luck with night attacks if I'm around 2000 yards.
Depending on weather conditions of course. I "Shoot and Scoot", so anything closer, and I dont have time to get out of visual range before torpedo impact.
The addition of Wolfpacks will be a GAMECHANGER.
Again, great job on your Modpack Bubblehead, and congrats on your Mod/Modder of the Year Award.