Hi Firstly, you will need to vent the room. The plants will need a constant supply of co2, and passing fresh air through the room will increase the rate of growth. If you don't suck fresh air into your grow room you will need to inject CO2, which can be a pain, but there's a cheap method of injecting CO2 with water, sugar and yeast. If you don't have enough CO2 in the room your plants will grow really slowly, plus you are wasting some of the light seeing as photosynthesis uses light and CO2 together. Hooking up a bathroom fan to a hole in the room can exhaust enough air. Here's some info on ventilation for your grow room. You don't have to have a carbon filter if smell is not an issue.

Those two lights are enough, but HPS lights are much more efficient than CFLs. You will get more light for every watt of electricity you use. Yes, HPS gives off more heat but if you are exhausting air it shouldn't be a problem. Are you sure you have 300 watt CFLs? I didn't know there was any bigger than 200, maybe 250. A 250 watt HPS should you plenty of light for a room of that size. Here's some info on lighting.

If you want to save money then don't buy the tent! It is only a couple of inches smaller than your actual space. You can buy enough reflective mylar sheeting to cover your room for 4 pounds. You said that you smoke about 2 or 3 ounces a month, if I were you I'd set up the perfect grow room to begin with, you will easily get your money back.

I'd recommend getting a 250watt HPS, an extractor/inline fan with some ducting and building your room with mylar instead of buying a tent.

If you are growing autoflowering strains the HPS will do for the whole cycle if you want, but you can add some small blue spectrum CFLs or replace the HPS with a 200 watt blue spectrum bulb for the first week or two, because vegging plants grow better with blueish light. You could buy a MH setup, but if you think that's too expensive just get the blue CFLs. Some digital ballasts allow you to use either HPS or MH bulbs, but they are much more expensive than magnetic ballasts.

If you still want to use CFL for the whole grow you will get enough light from about 300 watts of CFL.