If possible, paint the hood white as well to maximize reflection. FWIW
screw-ins at way too high wattage (2*23w over 8g) did alright for me, with assumption of much loss with restrike and reflection. I've also experienced decent growth with anacharis, hornwort, and java moss under plant-gro and "natural light" incandescent with floor and desk lamps. These are all stopgaps to doing it right (straight bulb flourescents, proper ballast and reflector - ahsupply.com) and playing with variables, but if you're the experimenting type...
(I've finally decided to do it right, and wonder why I didn't earlier)
Hope this helps.