Didn't the Germans typically salvo 4-6 rockets?
Perhaps. There are a lot of things that happened in the real deal that do not or can not happen in AH. In AH, if you're diving on a tank in a perfect 30° angle of attack and put your gun sight dead center on a Sherman, Panzer, T34, or even a Tiger you're probably going to hit WIDE regardless if you fire 1,2,4,6, or all 12. Like I've suggested, roll up a 190F-8 to a parked tank offline and see just where you rockets are pointing when you're nose is in the center of the tank (they hit the very tip or are wide). The only 2 exceptions are the Panther and King Tiger because they are longer, still I aim at the leading edge and not fire more than 2 rockets. Also, do a few test runs and record the impact (and observe while testing). In the real deal I'm sure it was a more of a "oh look, there is the column of T34's", and in they went on their 1 or maybe 2 attack passes before they got out of the area. I'm sure they lined up and let loose a volley of all 12 rockets knowing that they may not get a second chance, or maybe just a volley of 4-6 rockets knowing they might get another shot. What little I have read said that even though the pilots "aimed" the rockets, they knew the accuracy was not as a cannon and so the area effect was used. I'm not 100% sure. However, in AH, you can be rest assured where your rockets are aimed and where they will hit.
Trust me. Fire no more than two Pb1 rockets and for the first 2 rockets aim at the RIGHT edge of the tank (on a broadside shot). The two rockets will impact very close to center. If you aim center line on the tank your rockets will hit wide LEFT. For the second 2 rockets aim to the LEFT edge of the tank. Etc. Once you get the left/right figured out them you need to learn the rocket trajectory. That too can be tricky but let gravity help you.