the QP sul was also my favorite but if you are expecting it to fly in the range you specified you did not do your homework the 4d will cover you though
I have to agree. I flew both today for the first time and wind started at basically 0. I had to move to keep the 4D in the air but then as it picked up the QP SUL took over handily when the frame was flexing on the 4D(minor flexing, still inside it's range. winds never got over 8 mph today). Mine didn't come with yo-yo stoppers (I got it used, need to fix that) but it handled everything I could throw at it (admittedly, that's not much, but I liked the feel while doing my limited repertoire
The 4D isn't what I would call a "full size" kite but with both, you are definitely covered for zero to low winds...