To be honest I spent days researching lights. I have a small grow area, 3'x 4'x 8' and a concern of to much heat building up in the small area, I went w/ 85watt/350watt, 6500k, 4200 lumens CFLs. Actually the four I am using have done an excellent job. I just received 4 more to use in combination with the other 4. The new ones are 105watt/400watt, 3000k, 7000 lumen. Eight CFLs so if you ask me, I am saved by not building an exhaust system, save on keeping the area at about 74 degrees, save the large utility usage and cost. So I beleive CFLs are the way to go in cost as well as performance. I have been impressed with. The last set I bought cost about $32.00 a piece, so they are nat as cheap as you might think.
Regarding how much Gonja you can get? Who knows. Keep me posted on your indoor hydro grow.