When working with Meta Surfaces a good way to keep things well organized is using two 3DWindows at the same time (e.g. one as a central widget, the other one as a docked widget below). Using the filter options (points, curves, surfaces and name filter at the bottom of each 3DWindow) you can display only the surface in one window and just the distributional functions in the other. This way you can alter the functions conveniently while observing the immediate effect your changes have on the Meta Surface.