Thoughts on moss-covered background

[harpspiel]

Well, after taking severe casualties a few years back (very hot summer followed by cross-country move in winter), I'm finally ready to get my orchid tank up and running again. Here's the old thread:

http://www.orchidboard.com/community...ure-heavy.html

I'm looking to incorporate a mossy backdrop on at least one wall of the tank. I'm completely in love with this guy's tank, and would like to achieve a similar lush look:
https://www.orchidsforum.com/threads...project.14177/

I'm going to use a base of egg crate so that I can remove the backdrop from the tank when necessary, for ease of maintenance. What I'm wondering is what should I attach to the egg crate?
1. Plain Great Stuff, with orchids on tree fern or cork wired into it. But will moss cover exposed Great Stuff?
2. Great Stuff with Coco fiber glued to it - will that tend to degrade?
3. "Layered and carved" tree fern slabs wired onto the egg crate (as the guy in the above thread did) - sounds like a lot of work

Does anyone have experience getting a wall of moss established? All suggestions are welcome!