When I first saw the pictures I was just thinking the same thing; getting rid of that background. Sure enough, others thought the same wayLOL
And wow! It sure didn't look like a 100gal. You successfully reversed the illusion in making larger tanks appear smaller, whether it was pure intention or accident

Usually people try to make smaller tanks look larger by using proportionate plants with leaves and stems that are smaller, along with smaller shoaling fish.
You have a large tank, and large tanks always have more potential. Not only can you have more plants you can also have plants of any size. It really would help if you have more plants. It also will not hurt to draw out a design, which I emphasize to myself as well. It will not turn out to be 100% identical but that is the whole point. This is to give you a nice start. Once you have things set up it will undoubtedly be changed later as you see fit. The 'art' of aquascaping is 'cool like that'. It is always evolving according to the artist's own taste, which is developed and accumulated over time and experience. If you are looking for more plant varieties then Classified section is a good place to start. I don't know if your LFS carry enough to satiate your scaping needs, but I've always vouched for on-line shopping when it comes to plants.
Paul