What year is your Vegas? How much do you weigh? Other factors that contribute are the conditions you typically ride in, your ability and the size of board you are using.... North has wind ranges published on their web site (www.northkiteboarding.com) for the Vegas 6. I have an 06 12m and have found the range to be approx. 13>25 knots at 68kg. However, 15 to 23 is ideal... Not sure about the 05's..