I weigh 180 and I think I would be lit but still comfortable around 20mph, but if it stays there, I'm rigging the 9m.

150-160 pounds, it's hard for me to say. I haven't seen that weight in a while. Maybe cap in terms of being comfortable at 17-18 mph, but by then you are probably going to rig the small kite if it stays up. Again, I can't comment on what that weight feels like. I haven't been that weight since before kiteboarding started. Maybe for a smaller rider, a 12m and 7m are the two kite quiver.

The flat kites have much greater range but I don't see any reason to keep one in the air when you could also be powered on a much smaller flat kite that is much faster. If it is really gusty, that is one thing, but if you simply chose the wrong kite and the wind fills in like EB on a south wind, take 10 minutes to rig the smaller kite.