Application methods are similar but obviously we have gravity to contend with.
Acid stains are water-based products and therefore are runny and viscous. It is important to remember that in order to get a better more consistent outcome the stain should be applied from the bottom up. This is due to the fact that the stain will etch and color all un-reacted surfaces therefore if the staining is started at the bottom the stain that runs or drips down will make contact with an already stained surface.
Another method is to use a fine mist with multiple coats. Applying a fine mist so that it is just enough material to color yet avoid dripping. Often times 4 to 5 coats may be necessary. This can also allow for additional layering of colors to create an even more mottled color spectrum.