just look at the color temps of the bulbs your using and lumen output... go from there
for veg youd want 5k-7k (cool) id say and flower, around 3k (warm), if you can find under that, then go for it, but i havent seen any.. the plant will like the same wavelengths of light, regardless of the source (HID, CFL, sun) so just get CFLs with similar traits to the HID you WISH YOU HAD
haha, just playing i use cfls as well, they're cheap and coldblooded... simply savage