I don't know about the glosso thing under 26 watts but I do know that one of AH Supply's 36 watt kits over a 10 gallon still leaves some shady spots, mainly at the back of the tank. I'm considering building a DIY hood for my 10, installing the 36 watt kit plus the original 15 watt T-8 (with a decent reflector) for 51 watts, mainly to improve light distribution in the tank. So, my two cents: skip the 2x13 watt kit and go with the 1x36 watt kit. It really isn't that much light. Remember, the watts/gallon ROT doesn't apply for nano tanks so 2.6 wpg on a 10 would be considered "moderate" light.
Hope this helps,
10 gallon, AHS 36w, DIY CO2, Aquaball(!), plants, fish, more enjoyable to watch than the TV
5½ gallon desk-top, AHS 13w, Flourish Excel, AC Mini, plants, fish, nicer to look at than the CRT