I have two types of trees (cyrptomeria japonica Yoshino and thuja Green Giant) that I want to prune to encourange a single leader. The trees were planted just over 2 years ago as part of a privacy screen on a rural property. They were about 3 1/2' tall when planted and now vary from 6-8' tall. My understanding is that a single dominant leader will encourange vertical growth and improve resistance to damage from snow or ice. Which of the following (if any) ideas make sense? The first option would be just to have one leader. The second and third options allow multiple leaders, but encourage one leader to be dominant.

(1) Cut off the non-dominant leaders close to ground level. (2) Clip off some (but not all) of any new green growth on the co-dominant leaders. (3) Clip just past all of the new green growth on the co-dominant leaders.

I am starting to learn about different pruning methods and how differences will result in different signals being sent by tree harmones. In the mean time, I am hoping for some quick advice for the crypto and green giant before this years growth spurt. Thanks for any insights.