Four tubes of silicone was not enough. I covered as much of the background as I could with what I had and will have to grab some more on the way home from work tomorrow.
Getting the silicone into all of the little crevices was frustrating to say the least. My next greatstuff background will not be as detailed as this one. I used gloves but still managed to silicone most of the hair on my wrist to my skin...
For the coating I used a 50/50 mix of coir and peat moss. This is patted onto the silicone with extra put on top to ensure good coverage.
I got most of the bottom section and the top corners, leaving the middle for next time. I will let this cure tonight and get some more silicone on the way home from work tomorrow.
Tomorrow I will brush off the excess coir/peat mixture to use again. This will let me see which areas will need touch ups in the areas that were covered today.
Unfortunately the 3 branches on the left side are too heavy for the great stuff to hold up. I didn't put down a layer of silicone or silicone light diffuser to that section like I did for the back. The foam is peeling away from the glass and has separated enough that I can fit a screwdriver between the foam and the glass.
I will have to cut this section of foam off, rough up the back surface, silicone it back in place, and hope that fixes the problem. At least it happened now and not after construction finished.