When a plan part is active, I am use the PAN function (pressed mouse wheel) to position the content of a plan parts as good as I can. There is no fine automatic adjustment.
Regarding the 2D guidelines. This is possible. You can place 2D guidelines in a plan view as long as there is no plan part active, otherwise the lines are placed in the active view.
What you can do is, divide the plan view paper with horizontally / vertically crossing guidelines. And do the same in your 2D views to mark the reference point you want to align.
When you activate the plan part it typically overlaps the 2D guidelines in the plan view but the you can use your internal cross to bring internal and “external” guidelines in the right position.
