So in response to the creators' replies to my thread I purchased three bags of the newer FUSION FIBER stuff for $55. on sale.
Today I mixed a batch and applied it to my Styrofoam rough-cut surface. First I added 2 oz of Craftsmart Acrylic Paint (golden brown) to the warm water that I purchased from a Hobby Craft store Michaels for $0.33. I also purchased Tan and Suede colors as well two each for a total cost $2.00.
I mixed the Golden Brown in the water and then the fiber. After I had a paste consistency mix; I added some amounts of the other colors but did not mix as well to obtain a variant in the material.
Waiting the proscribed 20 minutes I then spread the fiber across the Styrofoam surfaces. My first impression of the spreading that I did by hand was that it nicely filled the nooks and crannies of the Styrofoam that I had placed with Great Stuff as a glue. I did have some very vertical surfaces that I had previously roughed up with a hot wire cutter so I did not need the drywall sticky tape.
At this point I am supposed to let dry for a few days; On Monday I will report back.