Does the duckweed serve any purpose, other than blocking light for the other plants?
I have a similar RCS tank. Glad to watch someone else's progress. Your moss wall is coming along, and it looks like you have tied the other mosses on the rocks, right? What if you pushed all the rocks to the right corner, with the biggest 3 sort of piled (still letting the moss show of course) and the fourth rock just beside them. Also if you trim the moss it will grow back in much thicker. The Amazon sword is ultimately going to be too big for this tank, but putting it in the back and bacopa in front of it will work for now.
Oh wait, if you do all that, it looks exactly like MY rcs tank.