Best PA for guiding

I believe that this is now done, and tested via the OT and a test case.
(We may wish to add more test cases for this?)
Hi, would you mind moving this closer to the call site since it's only used in one place? `SPTarget.java` is going away so it will save me a merge conflict. You might also want to get a stable handle to the `ITarget` here since you're racing with `setTarget`.