The size of your material does not matter. Because people use the probe to set their work-zero, they tend to associate work-zero with a corner of their material. Work-zero is the reference point from which the toolpath G-code was created.
Recreate your toolpath with a rectangle equal to the maximum capacity of your machine, and set the datum position to the lower-left.
Home your machine and set this as your work zero also. Since your material is oversized, this will be inside of the corner of the board. Your profile cut will now run along the boundaries of the machine.
You can refer to this post in another topic that explains the relationship between the CAD design, machine boundaries, and physical material.