Help in basics

[Krauter]

So I finally took the plunge (no pun intended ) and took the realism up a notch from just realistic sensors, no stable view to limited fuel, battery, CO2, and compressed air.
I ran with this setup for a good week and didn't find much trouble adapting. Of course this is only on Total Germany meanng operations don't take place that far from home. Now normally while cruising in friendly ports I stick to 1/3 speed to save fuel and then headup to 2/3 speed while cruising and patrolling. Once contact is made I speed up to full speed or flank of it's necessary. For underwater operations I stick to below 2/3 speed (full speed
only to evade ash cans)

Now my question is: what is an effective speed setting for cruising and underwater operations to ensure decent range and fuel consumption?

Also, I started a new career tonight with manual aiming and damn is it fun seeing your torpedoes connect and split the Tommies in half. My only
problem is when attacking convoys I find I get overwhelmed with data and cannot set up my solutions quick enough or accurately to engage multiple targets. Are there any tips or tricks to engage targets on convoys or targets in general for that matter?

Cheers and good hunting,

Kapitan sur Zee
Krauter