I think the worry about 6 cfls is heat created...and space. with an LST or Scrog, sidelighting is not very important. The spots on the leaves are lower right? I think based on the dark color of the leaves they are getting tons of nuts and could back off a bit there. Also, if the leaves get splashed when watering your basically folar feeding at way to high a concentration (Which will burn the leaves right where the splash is).
My yellowing is 2 fold. A long period of flushing, but also cal/mag deficiency that I seem to get due to my soilless mixture. However, it is fairly normal for the plant to yellow a bit at the end. The fan leaves are like a fuel reserve. By flushing and starving, you force the plant to use them as a food source. I have no proof, but I feel this helps with resin production right at the end of flowering