Whydo you have only these three types to choose from?
For sure I wouldn't get the RRD 18.9.
Since it is very slow! A friend of mine uses it and he hates it, since it is so slow.
And the difference between a 18.9 and 14.9 is maybe 2-3 knots. But when the big one pulls you there is no fun on the water. So get a smaller kite. The booster is a bitch to restart from water, if you dropped it.
If you can choose between only these kites, wait at least until the Super Type comes out and first test reports have been posted.
BTW I'mlooking forward to the Super type as well, since it just looks cool!!
So wait, it is cold anyway, or how are the temperatures in France?