I have used White Ground (the recipe from Frank Cassara's article in "Artist's Proof", popularized in Ruth Leaf's book) for decades, and have also developed my own recipe for a similar but more permeable ground ( PG-11) which is similar, and is used similarly. I have found White Ground to be too "hard" a stopout for my purposes. You can get great textural effects, but if your expectations are too specific it ends up stopping out too much, or not enough. The other stopout (PG-11) offers more of a range of tones, and a higher degree of control, though even with it precise tonal control is quite a trick. (Of course, precise tonal control with etchings is always quite a trick!) For those interested, here are some more detailed technical notes.
See Letter from Frank Cassara about recently released book Etching with Permeable Grounds by Richard Stauffacher.
See also Discussion of altering
the permeability of the Cassara White Ground recipe.