The last couple of weeks is when your buds really swell up ,I like my buds big, and I sure ain't gonna cut the light back. Especially after all the time an effort of trying to grow nice healthy plants. I might turn out the light about 2or3 days before harvesting and keep em in the dark to try to increase resin production but I ain't sure that's proven, but it seems to me it does help a good bit.