Personally, I think the 5 gallons is to big for a short(in time and size) grow. Unless that plants in there for more than 3 months then 5 gallons is good. But 3 gallon pots get the same results. My first grow tried two plants(same strain) one in 5 gallon pot, one in 3 gallon. The yeilds where the same. So I wasted 2 gallons of soil/perlite. With cfl's too you will want to keep them a short as poss, cause the cfl light dosnt travel distance very well(no light really dose) and cfl light dosnt penatre the foliage well enough to get big nuggets at the bottom of the plant. I upgraded to 600whps after my cfl's and the results are awsum. anyway back to your points,,3 gallon over 5 gallon. 5 gallon if going for 3 months. Just my advice,, fair enough the bigger pot will hold more nutes safer than a small pot , but aslong as you dont go mad with the nutes it would be okay. Also if your looking for gd nutes, liquid organic, I recommend Bio bizz, the bio bloom and topmax. the topmax is a flower stim, and works really well. I have seen dramtic results with the topmax. my only beef is the lack of Mg( magnesuim)in um.,,,, I have yet to see results with the bio heaven, but the bio bloom and topmax work. I hear good thing about that dutch liquid lig ht or somthing like that,,its ment for cfl's, but I cant mind and someone on here will have the info on that,
as for lights, aim for 10,000 lumens per flowering plant. so work out your lumens and see if youd have enough,.
Anyhow good luck and take it easy