Tom; what you suggested would work well, but what James was saying was that it's important that both sides of the MDf/plywood be laminated in order that any expansion or contraction is equalized by the laminate on the bottom. Over time the MDF would tend to warp from the pull of the laminate/glue. On countertops it's not as much of an issue as the ctrtop is firmly attached to the base cabinets. I'd go one step further and suggest that the edges should be sealed as well. In your application, warping would be a major issue...but on the other hand, it is a relatively small surface area.