I don't go by the wattage, but more the light output. A 23w cfl puts out an equivalent light output of a 100w incandescent bulb. The watts per gallon rule is basically a dead rule. Get the 23w 6500k daylight cfls.
Most stem plants will do well. Ludwigia repens, rotala rotifundia, and anacharis/elodea are good fast growing stem plants. Don't expect growth to be super fast, mine grow at about an inch a week. Also this setup is great for anubias, crypts, and java ferns. Most swords will do well also and water sprite. S. repens has done well under these lights. I get decent growth and have transplanted cuttings to all my tanks from the 125g. I trim my stems maybe once every other month. It's a hobby so it works out great for me.
Most stem plants will do well. Ludwigia repens, rotala rotifundia, and anacharis/elodea are good fast growing stem plants. Don't expect growth to be super fast, mine grow at about an inch a week. Also this setup is great for anubias, crypts, and java ferns. Most swords will do well also and water sprite. S. repens has done well under these lights. I get decent growth and have transplanted cuttings to all my tanks from the 125g. I trim my stems maybe once every other month. It's a hobby so it works out great for me.