Worried

Hey everyone i just started doing some LST and i also topped once. they are 3 weeks old and im wondering was this too soon? this plant has some decent height but my other two which are diff mystery strands are really short and very wide and bushy actually much wider then tall some of the leaves are just hanging in the soil. Im worred the the other shoots below are not getting enough light because the top is side wide and bushy here is some pics of my taller plant that what i think is in best condition just worried the bottom isnt getting any light. I need some opinions do they look healthy any criticism is welcome

Ps. when should i switch to 12/12 should i just wait and base my decision off anticipating size? ive heard they should atleast double in size when i switch to 12/12 cycle.