I have an 8 tube, 4ft T-12 panel I made and it uses 320W to make about 22,000 lumens if that. For 80W more using my 400W MH I'm getting 50,000+ lumens that. At a foot away the fluoros push the little light meter to 200. The MH hits almost 1500 at the same distance. I can run 2,4,6 or all 8. 2 are great for starting clones and seedlings then fire up more as they get bigger.
Makes a huge difference getting those plants bigger a lot faster. 4 tubes is fine for the small plants and that will still be wasting 95% of the light if not more. I use one 23W CFL for two little ones like that and add another one when they have a couple sets of leaves. Flouros are good for slowing down growth rates if you need to to time them better or to get more stretch out of something with real tight node spacing.
I'd try to get something a lot stronger for flowering. Makes a huge difference.
Good luck!