Back wall aquascaping question

[trilinearmipmap]

I'm thinking of attaching some things -- zoanthids, star polyps, maybe colt coral - to the back wall of my tank to let them grow there and create a backdrop. I'd like to get the whole back wall covered with polyps or soft corals. My rockwork leaves a lot of open space with the back wall visible in a lot of places.

Has anyone else done this, what are their experiences?