Downsizing

Hello everyone. My beast of a 150 gallon planted tank is dead and gone. It sprung it's second leak. I resealed it in January and thought I did an awesome job. With the second leak, wet carpet, and hassel of it all, I decided to take a break from large tanks. With my first child on the way, the wife wasn't too upset to see the large tank go.
Now I'm going through withdraw and want to start a small planted tank. I'm really interested in starting it emersed with HC being the primary planting, maybe some DHG.
What is the suggested watts per gallon for HC in a small tank setup? I'm looking at under 10 gallons that can sit on my counter top. I was thinking of doing a dirt tank, with flourite on top. Does this combo work in small tanks?
Thanks for the help. Any advice will be greatly appreciated.