Hi Andy,
I hope not to misunderstand but the behavior you described is already exsist in openpnp.
In my case after setting up the new board and importing the partlist, I insert approximately the position of the board visible from the dro (after positioning the camera).
Then I have two possibilities to correctly determine the position of the board ie through the fuducials or from some references of parts.
As shown in the photo below
clicking on the fiducial icon openpnp correctly verifies the position of the fiducials and at the end is positioned on the edge of the board that you can save to keep it in memory (and if you mark check fids this operation will doing ever job).
Or from the next photo
you can see how when you click on the parts reference openpnp asks you which parts to take as a reference and to position the telecara exactly in the center (my suggestion is always to include at least one mcu an oscillator and resistances and capacities for each mounting direction. horizontal and vertical.)
Sounds good?
LAG