Potdude, I don't know the difference between super and normal, but I would say that your light could be a little closer, say like a foot away from the tops of the plants. If the soil is drying out quickly then you probably need bigger pots. 15 litres are the best, but the bigger the better. Soil can look dry on the surface but as soon as you stick your finger in you can feel the moisture. if it's dry 3" down then this is when they need watering.
bombdiggity, yeah these should be fine. remember though that you want your flourescents about an inch away from the plant, and the hps with your wattage should be about 12". Might be hard to set up though, you'd maybe have to use the flourescents for side growth. Which is all good, you'll just have bigger buds than usual on the sides.