cannabis seeds in my experience usually open between 24-36 hours in wet towel. some people wait longer but i stick em in the coco as soon as I see em open. couple days later they'll be breaking ground.
Trimming techniques and tips
Low stress training (LST)
Pruning
Topping
Fimming (FIM)
Defoliation
Mainlining
Lollipopping
Super cropping
Splitting stems
Trellising
Root pruning
to give you an idea and what to search for