I a board which is used in two different systems. In one the board needs to be bigger than the other.
For this I use two board outlines.
one defines the smaller board the other defines the larger board.
The board is manufactured to the larger size and a v groove alone the inner board line indicates the V groove. So I can easily make the board smaller as it snaps along this line when placed in a vice.
This requires a written instruction to the board manufacturer.