With only 10 watts over the 5 gallon aquariums, you really don't have much light for a 5 gallon. The WPG
"rule" breaks down over those small aquariums, and you need more than it indicates. You'll want to stick to Anubias, Java Fern, Java Moss, and Crypts. Also if the bulb is 1/2 daylight and 1/2 actinic, you'll have even less usable light. Make sure to use completely daylight bulbs.
For substrate check out the planted tank forum. Theres a Read This First sticky that has links to threads and articles with great information on all things to do with planted aquariums. I believe there's a thread specifically about substrates, and at least one of the articles covers substrates as well.