Are you using a light mover to cover the 7' long room you are trying to grow in? If you are not you may need to study about light penetration and do some calculations. One of the reasons your yield is not up to par for all your work is environment. You may only have 1/2 of the proper environment required to grow bigger buds. What is the RH (Relative humidity) of your grow room? Just observed a few things to start you thinking about