Nice tutorial and overall blog entry. I like that you make a point to recommend that the bath bombs should be stored somewhere dry. I remember making a batch of bath bombs early on and leaving it overnight next to a window, the next morning I discovered the had reacted to the moisture in the air. D'oh!
As for your recipe itself, it think it's interesting that you used spritzes of water instead of the usual witch hazel. That said I have no idea what the benefit of using witch hazel over water is.