I didn't think I did either until I tried it--a lot of the time we find out we're better at things than we think. Go for it and see what happens!
There are a couple of things about this build that are easy to do and saved me time:
Most of the background is layers of foam siliconed together, but the left wall is a piece of curved cork and some driftwood siliconed to the glass (hides the pump and tubing), with sphagnum moss over the visible silicone seams.
The driftwood on the right side of the back wall is siliconed directly to the glass (more stable than attaching to the foam) and then the foam is built out around it. There's a small mesh planting basket in the curve of the driftwood that's siliconed in and covered with sphagnum.
The overhang at the top (which provides the spraybar channel) is layers of foam and then a couple of pieces of cork to form the "channel." The cork is siliconed to the glass along the upper edge and is supported by the foam layers (and siliconed to it) along the lower, so it's in there pretty tight. Eventually the plants will root into the cork (I hope) and completely hide the tubing.
The pump tubing and spraybar are pieces of flexible plastic tubing (1/2" ID, size to fit the pump) and a "T" junction. I cut the drip holes into the tubing with an x-acto knife (watch out for fingers, those knives are sharp!). I made the channel just wide enough to hold the tubing, but did not silicone it in--you never know when you might need to take it apart!
Rather than cut the layers of foam into pieces (giving a square edge), I broke it (this came back to bite me in the but later--the nooks and crannies along the edges were hard to get the drylock into). I roughed up the foam with a wire brush and knocked off the sharp edges with a rough sanding block (messy but fun) to give it some texture.
I laid all the pieces out and did a dry run before I started siliconing. I probably tweaked things here and there for the better part of a week before I actually started to seal it together. Even once I had started with the silicone, I still tweaked the design by adding layers or reshaping pieces as I went. I spent a lot of time at each stage just standing back and looking at it to decide if there were any changes I needed to make.
Hope this helps a bit!