Hi!
I'm kinda on/off player and though I have played sh4 and 5 for years, there can be like a year between active playing "seasons". So I'm not very hardcore player, but Maybe there is something to adapt from my playing style to yours. Have to say that Everything I know is basicly read from this forum and I have a big respect for all people here who share their knowledge and mods!
But to the point. I play with sobers mod list, real nav and realism settings on except ext. cam, but that's just for the beauty and screenshots, I don't cheat with it. I navigate to the patrol zone surfaced, usually 9kts mainly because its easy to calculate in your head the distance you travel. You travel about 100km in 6 hours. When approaching hostile waters, I drop speed to 6-8kts and make dive every two hours to about 30-45m to use hydrophone. I usually don't tc over 32x when I'm patrolling. I listen few minutes, no luck, surface again and over again.
When finally something comes up, i turn my boat towards the contact and wait to see which direction it goes. No matter if it's going away. I don't calculate the exact speed and course of the contact at this point, just rough estimation where it is heading. If in ten minutes it's bearing changes for example 5 degrees, I take boat to surface, take course maybe fifteen degrees ahead it's bearing, order flank ahead and steam on maybe fifteen-twenty minutes, then below again, new listening and course correction accordingly. Eventually you get visual contact with the target.
Now is time to get to good firing position. Depending on the weather keep very good distance to target, that you barely see it. If it was moving away, you have to get around it. Make an educated gues of targets course. Choose your own course the way that target bearing is like 60-90 degrees on port or starboard. Try to keep the distance. I used watch officers range-estimation as a reference before, but after a while I didn't need it anymore. Silhouette of the ship or ships should get longer but not bigger. When they start toget shorter again, you've passed them. Continue until aob is about 30 degrees. Dive and decrease speed. Start to approach target, keep target about 45 degrees on your side. When you get closer be carefull with the periscope, don't keep it up too long at a time. When aob is almost zero (depending how far away they still are), stop and turn boat that bearing is almost 90 degrees. Wait and when they are close enough, start identifying and collecting data for torpedo launch. Make corrections for your boats location if necessary. Don't keep your periscope too high or too long on the surface. I try to launch always at point blank range, under 1000 meters, so my data doesn't need to be 100 pecent correct.
That's about it, sorry bad language and if it's hard to follow, I got suddenly busy while writting this! But all in all, this method is based on estimations and guessing and I like the rough feel of doing things!