I fine tune it over time. It is trial and error. On the run into the target I would stay at full speed as long as I could, but when getting close enough to the fleet that you might be shot at, then slow to 40 knots and turn to intercept.
After you finally get the enemy ship to sit in your gunsights without drifting either left or right, you are on course. The question then becomes when to drop torpedoes, and I would suggest you get as close as you can.
Or you can just blindly fire away and hope. That has always worked in the past for everyone, right?