Fuck wrong button! Probably necessary concidering the amount of light your losing. I cannot say yes or no about hitting your goal but if all your factors line up theres no reason you shouldnt hit your mark. Some people will argue what im about to say and thats ok because I know what I know and that is no other method of growing can compare to DWC. This I one reason im able to get the speed of growth I do and the mass, oil production, turpenes, resin, and crystals. Soil growing just does not compare to hydro. Now soil grown indoors is better than outdoors buts thats a whole other thread. Whether you should add 600w more I cannot say because I dont know you temps, humidity or anything else. If you were in a tent or had mylar walls I would say no but like I said with the amount of loss you may need it. It sure wont hurt as long as your temps are under control and your not stressing your plants. I know someone that gets 7oz out of one plant and a 250w light.