Planted 20g light question

[Readingexcalibur]

Standard Aqueon 20g. would a Aqueon Freshwater T5 dual Light from Petsmart cover my in the lighting range. I get the 2w per gallon rule, but from what i understand you can add the two bulbs together to get your wattage. that gets me close to 40watts. I have some African swords, but want some sort of grass.

Have Eco complete substrate, will be trying a DIY Co2 as well. Thanks!