I think it would just complicate things. It works for 3D printers, but I don't think it has any benefits for CNC router. Also, if you will have two motors, one on each side, then you should zero both because eventually they will be out of sync, and that will cause problems. If I knew that I don't need the gantry clearance I'd make the sides lower and would reduce the clearance that way, or would raise the table to be able to reduce the need of moving the gantry down to it's maximum extension.