Hey, gorilladave, how's it going?
Basically when you look for cfls, take your cell phone, it probably has a calculator. Then divide the lumen output by the watts. This will give you lumens/watts. This is how efficient a specific bulb is. The higher the number, the better.
If you can find Deluxe or some other symbol of high-end bulbs, they usually are more intense and have a broader spectrum.
6500k are better all-around and for veg. 2700k are better specifically for flowering as the spectrum induces production of flowering hormones. You can either replace 6500k bulbs or mix them with 2700k bulbs for flowering.
Check my signature, my thread on CFLs contains charts for their coverage.