if they are 6 inches then no should be good. used cfl's as well used 6 of em on 3 plants 2 per plant at 6 inches from the plant. plants did great. then i upgraded to a 75W led kept the LED light super close at 5-6 inches from the top cfl's for side lighting at 5-6inches no issues. i then upgraded again to a 2000watt advertised actual draw is in the high 300's 375-392 depending where i get the info from that is some state 375, some 385, and the company states 392. can't keep these ones close plants start to get heat stressed at 18" so i keep them 24" high but under 30 max. i really dont mess with cfl's that much i mean like canuk showed i don't want to deal with cfl set ups like that i rather just invest in better lights over all.
all i can say is invest in better equipment when you can and you won't look back. cfl's can grow some nice plants you just need a lot of them and i doubt they can grow anything as big compared to say MH and HPS/LED's lots of cheap LED's out their i bought mine for only $220 it's not the best in the world but fucking better then what i was working with so i can't complain.