As experience if you big guy you should choose the big boards also that if you small guy you should choose the small board.
What’s happen when you choose wrong size?
If you choose the board than your size you will go fast and difficult controil the speed (In good condition wind) opposite if the board less than your size you go slow and difficult in upwind.
so what is my board size ?
I’m 70kg and my board 133 – 135 cm * 40 – 41cm. in fact i used the cabrinha x caliber board. It’s so good good for me.