you are gonna need at least 2 feet of vertical growspace (i.e. from the top of your grow medium to the height at which you are too close to the light). This is is if you scrog. if no scrog then you will probably need even more height.

you can do it with HPS if you cool tube, and you can run a double cool tube if you run both inline. HPS will give you a better yield, and in my experience cfls are a pain to work with since you need so many bulbs. It will be warmer, so a cooltube is a must. I run a 250w hps and my plants can grow right into the cooltube without getting burned. I would recommend a good fan if you are going to be going thru a carbon filter since this can slow things down a bit. a cheap fan will get you cheap circulation. thats why I had to put 2 of them together to get enough flow. If you vent inside your house expect it to get warm.

if you are still planning on the double chamber, double light tube, then i would connect the 2 chambers at the top as well to allow the stinky air to get from the 2nd (in air flow) chamber, since there will be no opening in that one.

the nice thing about dual chambers is you will have a veg chamber and a flower chamber, so you can harvest every 2 months or so, you lucky dog