Pepetual grow w/mixed lights. Need some input

I've got a bit of a dilemma here, because I'm trying to figure out some way to get my grow operating on an every other week harvest schedule (2 plants per harvest) without needing to purchase any new HID lights.

I currently have both a 600w and 400w with both MH and HPS bulbs, and my plan is to veg under the 400w and veg under the 600w, but I can't to seem to figure out any way for a single 600w to handle 8 plants that are anywhere between first day of flowering (approx 20" tall) and ready to harvest (around 5' tall). What I'm wondering is if I could just get myself some supplemental lights (T8's or CFL's) and use them to help make sure the shorter flowering plants are getting enough light and not stretching towards the HID that will end up hanging about 5' above them?

Will it work, or am I going to have to have one HID light to handle the plants that are between week 1-4 of flowering and another to carry them from week 5-harvest?

Some cfl hangers should do the trick. I use the mixed spectrum 125 watt ones and find them to be great. They are cheap and the little bit of blue light does wonders. I'd get a couple of them off ebay and hang em down to any dim areas if you dont want to flex an additional HID.

Start flowering when your plants are only 8-10 inches tall.
You'll be able to fit more plants under the light footprint.
By the time they're at peak height they'll be around 28-32 inches tall.
You'll still get at least an ounce per plant.

Bong,

Problem is that 1 oz per plant isn't going to meet my needs, so I'd have to add more plants, which would definately mean more lights. The strains I'm growing should yield about 3 oz per plant on a 12-14 week growth cycle (I'll be starting them from clones that are about 4" tall), which leaves me with about a 1oz cushion per plant on the minimum yield I need. If things go normally we end up with a little more then we need for our own use, and if something goes wrong we should still be able to get enough of a harvest to keep us from needing to pay dispensary prices before the next harvest is ready.

Superlevs,
Thanks for the input. I thought they would work, but i wanted to hear from someone who has actually done it before I made a final decision or spent any money.