In addition to the remarks above I would add that I found the magnetic and electric torpedoes to be very unreliable in general and have stuck with steam torpedoes for reliability reasons. As most of my attacks are at night or against freighters the chances of evasive action are fairly limited and indeed I now generally fire just one torpedo at each target. It is generally sufficient for the soft targets. Fishing boats and small freighters I will use the deck gun if the tactical and weather situation allows.
Also don't forget when starting a Wolves of Steel campaign to save in the bunker and then reload before you do anything else. This is fundamental according to the installation and operating instructions which I shall assume you have read
There are many excellent tutorials on youtube for the wolves of steel, and it is highly configurable via the options file editor viewer.
Initially in the Polish campaign I would concentrate on getting the basics right and build some experience. Things like minimising wake, boat aspect to target, firing position- all have a massive impact on the success or otherwise of your mission. As you leave harbour there are friendly escorts that you can practise firing solutions on, and also positioning your boat for an attack. Minimise periscope time too- don't ever leave it up, try to keep it to under 30 seconds maximum and preferably 10 seconds should be sufficient, keep the speed down to under 3 knots maximum to reduce periscope wake. Get your sonar man to track the target instead.. before you put it up ask yourself what you are looking for- if its a quick 360 keep it at that. Don't put it up to just look at the target..
Good luck Captain.