Looks like you are on the right track there buddy. Im also about to pop an Afghan Kush Ryder as I have read they are quite the smoke, especially for an auto. I would definantely get some sort of ventilation in there. Try making a passive intake with the exhaust fan pulling air out and pushing it through a carbon filter. Its super easy to make an effective one if you search the forums. Looking at your grow cab, Im estimating around 200 cfms are needed to keep the air exchange rate of 5 mins or so. Also, try to get your plant a little closer to the light. I would say about 2-4 inches. Especially since its a CFl light, you need all the lumens you can get. Dont get me wrong buddy, you will grow great bud with the CFL, you just have to get the light close as humanly possible to the plant without burning it. Is that bulb a Feliz 125 watt bulb? I have a Feliz 250 watt 6500k bulb with a Suns System reflector that I'm throwing in my cab. Our grows should be similar and will be following your grow. Best of luck to ya brotha.