.. length for height, width for weight! Then plus or minus abit for the wind extremes.
For my height (6'4") and weight (120 kg) I regularly use a 144x 46cm, but we have the bottom end of the wind scale and I must admitt I had to get used to a bigger board and once I got used to it, I'm really happy and don't know any different.
Depends on what kites you like to use too, and how hard you like to drive them. For me I like to be as powered as possible using as big as possible, and use my edge to control the power of the kite, where as the missus likes to cruise along with the kite being just right. If you use a bigger board you can afford to use a smaller kite, or, if your like me, and wanna feel well powered all the time, use a bigger board and hang on.
Anyway, just one more opinion thrown in the hat!
cheers,
Robbie