I have now assembled the materiels that I will use to set the tissue layer and add some more snow.
Woodland scenics scenic cement is essentually white glue and water mixed but more expensive. The great part about using this stuff is that it will leave no glossy sheen to whatever you spray it on as it dries.
Woodland scenics snow is basically shredded foam and is the best materiel that I have found, thus far, to replicate snow.
The tissue, I am using to build up and shape the groundwork in the area around the droid using the scenic cement as a fixitave. I then sprayed the whole dio, shook on some snow, and then sprayed the dio, again. I probably should have touched up the original layer of snow with paint in the dirty areas, first, but forgot about it. i can do that later, if it is necessary.