This thread is a great inspiration for my next tank - the layout is absolutely stunning! I just re-entered the hobby after many years of absence (this is my first post on this board), and I just set up a 40G Breeder sized tank. I'm just cycling the tank and I haven't even purchased the lights yet.
Interestingly enough, for my 40 gallon tank I'm thinking about purchasing the UP Aqua Pro Z light as you are using in your setup. From using Google, I see that this light is used more prevalently in Australia than it is here in California where I live. However, my main LFS owner recommended it, says it's very good (and he's selling it for US $130, which I think is a good price from a store). You said you had reservations about using the light for this setup, I'd be curious to know what they were. I'm sure it would be strong enough for such a small tank, but perhaps not for my 40G? I'm thinking that if it doesn't work for my 40G, I can use it for my 12G long. You got the 36 inch long version of the Aqua Pro Z, right? To my knowledge the 12G Long is 35.4" inches long, so it should work.
Interesting also to read about your experience with ADA Amazonia. Someone recommended it to me for my 40G setup. After researching it online, I decided to go with a layer of Eco Complete topped with a fine silica based sand that looks similar to what you're using in your setup. First I felt the ADA Amazonia was to expensive, and the LFS owner I mentioned (whom is very knowledgeable) recommended strongly against it due to the fact that it disintegrates.
Again, beautiful tank and great job. It's easy to see you're a designer by day, aquarist by night!