I flew my 16One yesterday from around noon until about 1:30 - check out the graph below. I used a beat up, old 6’2 surfboard with a lot of rocker (but lots of float), and was able to stay upwind and catch waves without working the kite, while everyone else walked the beach or watched! I weigh 150 lbs. This kite has the low end of a good 18-20m C kite.
http://www.ikitesurf.com/windandwhere.iws?regionID=138&siteID=225&days=1&Isection=Wind+Yesterday