Unless you are planning on sanding off the coat of Watco, brushing on liquid ammonia or dye or stain may color the top and bottom differently. If I remember, George Frank, when a relatively new employee, saved the day when oak furniture installed in a bank was judged too light. Presumably a complete finishing schedule was already on the furniture. He suggested closing up the building for the weekend and placing trays of ammonia throughout. By monday the furniture was just the right color.