If I decided that a batten were needed, I would keep it simple and simply screw the batten on, making sure that the slots were elongated to allow for movement. With a 1 1/4″ thick top, there is plenty of thickness to take a screw.
That said, I don’t have a good enough picture of the design to decide whether anything is needed. In many trestle table designs, the trestle legs themselves are long enough at the top to provide the effect of a batten. Shaker trestle tables are good examples.