Nice going Hoppy. I've been following your thread with great interest. I'm going to be setting up the exact same tank in a couple of weeks! Perfecto hood, Diamond Black and Flourite Black Sand. I had a couple of questions which I was hoping you could answer.
1) How thick was your Diamond Black layer and how thick was the Black sand?
2) Did you need to dose/spray any ferts while doing this or did the Diamond Black provide the required nutrients?
3) In retrospect do you think the upgrade in lighting was critical to your success?
4) When you do flood your tank, what is your Excel dosage going to look like to prevent melting of emersed leaves? If this is a higher dose of Excel to prevent this melting, can it be phased down to lower levels over time without melting and the potential mess it might create in your tank? I'm asking because I'd like to start something similar but I'm hoping to dose Excel just once a week and not shoot for large amounts of plant growth.
5) Lastly, do you know if anyone has successfully grown Dwarf Hairgrass using this method, or if it is possible? Would anything need to be changed?
Sorry for the barrage of questions

. I'm looking forward to hearing back from you. Good luck with the tank flooding!