click on this link and scroll down and read JB post in regards to kites sizes and weight.
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=31422&whichpage=1I am close to 90kg wet and I have gone a 9 and 12 combo , the cults come with 20 mtr lines and you can get 4 mtr extensions if you want.I ride the 131 thorn and 5,5 fish.
If you ride waves dont bother getting the extensions but if you ride flat water then it might be worth your while.