Under the screen talk.....
What a difference a little playing around with early training and floater screens can make. The type of plant makes a big difference as well.
A seed plant with no early tie down training. It was planted and left to grow normally. Did some heavy super cropping on it and it finished in a floater. Not a lot going on under there.
Stepping it up a little is a normal clone that was trained down as soon as it rooted and was up potted.
The flowering clone is the winner under any screen. It will out perform all others. Once regenerated every leaf that emerges a branch comes with it. Doesn't take long to fill a space with that kind of growth. These clones take an extra step to reveg but they are worth the wait.
Cleaning out the undergrowth. Well, that's totally up to you. I've done it both ways and can't really see any difference.
My main goal in cleaning out undergrowth is one, to take clones and two, to increase ventilation on a plant that is clumped up and leafy.
Does removing growth below make bigger buds? Some believe so. I do it for other reasons but it may help.