4-bearing method is to be used for targets that are far away, otherwise you have a PERISCOPE...
and special instruments you can use with it (disks...). As a good Kaleun you must be able to raise periscope and find a solution immediately for firing in the next minute if need be.
And guess: for this there is no tutorial...
Don't let you carry away by all these tutorial videos and complex solution methods. Use your instincts and your OWN methods. That sounds stupidly simple, but all Kaleuns had their own methods for getting tonnage, some with very bolt tactics (like Otto Kretschmer going inside convoys because he understands that he's invisible, or Dick O'Kane the 'Wild' man etc.). Find out what best suits to YOU. In war, and WWII there is no forum or advisor that helps you...
But of course: go on asking questions!