I did CFLs for a few years and switched to HPS lighting two years ago. Buds are twice as big and much tighter and heavier. You better be good for goodness sake 
I really hate to disagree with you but you can have to much light.this is most obvious with "led burn" to much light will shut down chlorophyll and could destroy it. lighting levels could be higher with HPS because of the spectrum they produce and the weighting that spectrum gets on the lumen curve (http://www.carbonlighthouse.com/2014/02/13/683-lumens-per-watt/#prettyPhoto) but with fluorescents 4000 lumens per sq ft is considered optimal and with led 40 to 50 watts (actual power) is very common.many plants actually shut down in mid day to protect themselves when grown outdoors and the lights we use tend to have a more focused spectrum than sunlight especially with leds* Lighting is not the easiest thing in the world for me to explain but I will do my best to help you, this is a disclamir for a lengthy wordy explanation.
The thing about lighting is penetration. The different lighting sources create different depths of penetration. Meaning that you have maximum lumens at say 6 inches with a 400watt 12 inches with a 600 and 18 inches with a 1000watt HID(I do not know nearly as much about CFLS or LEDs many others here do though and can probably chime in)
All that means is that if a 1000watt HID(or in your case a 184watt CFL) puts out X amount of lumens that is 18" away from the bulb, when you start to get further away the amount of lumens decreases exponetially(very very fast) so at 24" away you will have significantly less lumens.
Lumens make photosynthisis occur, so no matter how you position your CFLS there will be certain portions of the plant that are closer, thus getting more lumens and making more photosynthis, and some are further away getting less and making less.
So to sum up your question as stated above you really need more light, IMO and it is just that an opinion to get top quality nuggage 75 actual watts of lighting(no matter how you get it) is needed.
To give you a reference I have a total of 3.7m3 of space(very similar to yours) 8.5x4.5x9.0 and I have 2 1000watt MH/HPS's I am growing 6 plants in hydro. So I have a little over 300watts per plant or 533 watts per meter cubed. I will admit I might have overkill but again in my humboldt opinion I think it better to have too much light than not enough as I can always turn down my ballasts.
If you can get more lighting I think all here would agree to get more, if that is not an option try and position your lights as close to the biggest plant as possible and grow out 1 plant. I think you will get a better quality and yeild off positioning your CFLS around the biggest healthiest plant and make sure you keep your temps in check.
I hope this helps sorry for the book long post, good vibes comin your way for sure! Keep at it you will do well, it seems like you have a great head start!
would you guys take a chance on this for $50 includes shipping.?