Bend stalk? or top 12"(inch) plant?

I'm doing a 2x2 screen grow. I was planning to top plants to cause more branching at screen level but one is 12" tall, other are about 7".

Should I cut top of 12" to even the height with others (which I would pinch also), and use the top cutting as clone? Is it hard to get such a cutting rooted?

Or

Should I gently bend the stalk/trunk 90 degrees at the same height as the 7" and let it grow horizontal under screen?

Is there a height requirement for vegging below screen?
Do plant need to be a certain height, ever?

Is it better to grow the main stalk/trunk horizontal under screen or to pinch top to cause more branching?

if I were you I would bend it, just try not to snap the stem and where the bend is it will make a "knot" when it heals...it would increase your overall yeild