They are tall! The tallest one is 4ft at least. I haven't put a tape to her and measured but i am 5'11 and it's to my chin, easy.
My tent has 7 feet of head room.
You could LST these and get some insane yield numbers i bet. It might work for you, but i think you will have to do some training. The samurai jacks so far, seem to be a bit smaller. So those might be an option also.