Supplement 600 watt HPS with CFLs?

First time poster and second time growing. My clones are in week three of veg (FYI, I like to veg my plants for a long time). They are starting to stretch a bit under the 600 watt HPS. I'm doing a little LST on the worst offenders, but does it make sense to supplement that with some CFLs on the side?

Here's the setup:

Strains: White Widow, Harlequin, Romulan, Afghani Purple
Medium: Soil
Nutrients: Mostly Botanicare line
Light: 600 watt HPS on a dimmable ballast
Intake: 6 inch inline booster fan from outside
Filter: 6 inch x 16 inch Phat Filter
Exhaust: From filter through reflector out through the wall.

Should also say that the hood was raised for the purpose of taking the picture. It's actually close to the tops of the plants.

yes, Not sure if you know but hps is not for vegging its for flowering, you should have a mh conversion bulb in place of the hps bulb....Its always a good idea to use floro power for side lighting... I use a 600 watt hps for flower + around 250 watts of cfl,s for the sides....

Ya, I should pick up a mh bulb since my ballast can handle both. I don't think it's a total necessity, but it would help.

MH isn't necessary, lots of people use HPS for both. But your HPS will last longer if you have a MH and the node stretch isn't as bad.

I plan on using HPS all the way through when I get my system, then after harvest and I find a few friends looking for medication, I'll invest into a MH bulb