My first grow. Eliminating 2 of 6 plants

Hi i am growing using a bubbleponics system from SHYDRO. THere are 6 site and 6 of my plants are looking great, But there are two that are scronier than the others due to spacing issues. I am considering eliminating these two and spacing out the others so they can have more space to grow. This is my first grow so some help would be much appreciated. BTW, the 4 larger plants range from 10-14 inches and the two runts are 8 inches.

I am way up in Canada and I cant see see the plants from here. Can you put some pics up, I have a crappy imagination.:)

sometimes them runts turn into bitches and the faster growing taller could be boys that want to tower the ladys.