and one more thing
Im not even using mylar at the moment white walls on two sides and a tarp thats silver on the inside and brown outside making the other two walls. I am running a 1000w hps with a hortilux bulb and a 4 bulb teklight and two 2 bulb 2x overdriven t8 4' shoplights in a space about 8'x10'. the plants are more towards the center also and recieving plenty of light.