(1) To split the layers I use a long piece of strong thread, center on middle of layer, then pull through from both sides, cleanly slicing the cake layer in half. -- A serrated edge knife works well also.
(2) This is a "make ahead" cake. I believe the ideal time for moistness and flavor is 5 to 6 days in advance, although it will keep up to 7 or 8 days in the refrigerator.