One more thing to consider is that, if my understanding is correct, there is a gyro involved, and if you have a SPI being generated on a truck via the TGP, and you pull a tight turn, the gyro can't physically keep up with the turning of the plane. So when you come about and are unmasked again, you will find your SPI some distance to the left or right of where you had it. It's a physical limitation of the gyro and it's modeled in the sim.
As others have said, see a target, make a markpoint.