The process you're talking about is called defoliation, mainlining takes place when the plant is small.
It looks like they are starting flowers down in the bottom I would leave them and tie the upper branches back a little bit so the light can penetrate. After a few weeks of flower and it's got a thick canopy I would start by the base of the plant and working my way up just pinch or snip off the little branches that aren't getting light. But i wouldn't cut just yet.