I have been riding Rebel 09 6m and 9m in the past months. I had some very powerfull sessions and low winds too it really feels so good!
At the beginning it felt like too powefull when compared to previous 2007 and 2008 year models. Then i found i was sheeting in too long when hit by a gust. It is a habit i got from my faithfull 7m 2007 Rebel that required it to ride well in very gusty wind.
The Rebel 09 6m is my new marvel kite. I ride it from VERY little wind to 35++ knots. It is fast and very responsive even when fully depowered.
The thing i most appeciate is the fact that the kites are always where they "should be", drift very, very well and the few times they hit the water, came out immediatelly.
Bar feedback, pressure, stall resistance and reaction to input is PERFECT for me.
At the beginning i was playing with 5th line length and at the end put up the production setting. So my recommendation is to leave things as they came. Just plug and play! By the way, i never close my one pump clips. Just pump and ride.
6m, 8m and 11m might be a great combo too!
I always use 20m lines and ride surf boards 90% of the time.
I rode the 6m Evo 09 and will stick to my Rebels