I'M FLATTERED that I would have that much influence!! After reading my post you decided? WOW!!...and I have been getting tons of emails too from people enjoying my advice and following me. This is pretty OK by me! Thanks for all of your support. If you continue to feed off of it, I will do my best to keep it flowing. OK..enuff about that. Now, about your kite and body weight.....
I only weigh in at about 165 to 170 lbs myself. My brother is smaller than I am and weighs in at about 135lb. For me, I like my 17m as much as my 15 or 13 for that matter. Depends on the wind and my mood...and sometimes I like to ride SUPER powered. My brother though on the other hand has not much use at all for the 17m Fuel. When their is just enough wind to keep a kite in the air, he can get on a floaty board like the Manta or LFT and be pretty well lit on the 15m. With that being said, what use WOULD he have for the 17m? But you weigh a bit more than he and may not have such a floaty board to use in light winds. If I was you, I may not consider going as big as the 17, but I would surely not go as small as the 13 as my biggest kite either. Should prolly just rule out the 13 for now.
So, with the 13 out of the equation, that leaves us with the 15 and 17 for you. Here's the thing. As stated above, I can go in as light of a wind on my 15 as I can my 17, so I don't really see riding in lighter winds on my 17 than I can my 15....BUT, if I wanted MAX power in those light winds, then I'd use the 17m. However, I can hold the 15m down in more winds than I can the 17m. So if I were to have to pick just one, and I was your weight(you didn't mention skill level, so I am assuming you can ride), I'd probably go with the 15 because with it I can ride in super light winds up to a pretty good bit of wind. With the 17, you wont be able to hang on in as much wind. IF riding around in 11 knots or less IS what you have in mind only for the kite, then maybe even go with the 17m...just be aware that it will be one bad bitch in heavier winds.
side note: if you arent an accomplished kitesurfer, please do stay away from the 17 for now...if you are just beginning, you may be right about getting the 13, but you may need a larger board. Beginners are much better off and a whole lot safer starting on smaller, less powerful kites and bigger more floaty boards. That way, when the shit hit's the fan, and trust me it will from time to time, you wont be getting worked so hard by so much power. As Rick Iossi mentioned in a post on here somewhere, when we fall or eat it, our engines(the kites) don't readily shut down and stop pulling us.
And finally, if you aren't a beginner and you already own some kites for other wind ranges and are just looking to add a big one for light winds, for sure don't do the 13! That brings us back again to the 15 and 17. This would be easier to answer if I knew what kites you already have, experience, and also important is what boards do you ride?
With knowing what I do know about you, which at this point isn't much, I think I would have to recommend the 2003 15m SS Fuel.
Feel free to email me with more questions if you'd like or you wish to discuss it further based on your OTHER kites and experience...or you can put the questions here. Sometimes they can be overlooked here though as I haven't the time to read everything. I TRY though.
Hope this helps. Talk to you soon.