My two cents. For the bigger guy.....lets say over 200lbs+, its all about getting on plane, not just staying on plane. I do agree that a big dude with a big board and a 14M kite could ride once on plane and apparent wind is created....but its getting that weight out of the water in the first place where the problem lies. That is where a bigger kite can help IMO.
Scott......already tested the weight belt theory. I will admit this online and you all can chastise me.....so here goes. My daughter who weighs about 35 pounds has ridden with me in a Slingshot Kite bag on my back up at 3R. Conditions were light 10knots and water was smooth. With the extra weight it is very hard to get up and get out of the hole...I am 155 pounds....with her weight that makes me 190 pounds. So adding another 20 pounds to the equation would put me in a position of diving the kite and never even getting into a standing position to create any kind of board speed. We all know smaller kites move quicker and have less drag, but its that dive of the kite into the power zone that I see big guys with smaller kites struggle with. There just isn't enough pull there to yank them up in a standing postion.
So Big G is looking for opinions here so my vote is go big on the board and the kite especially if over 200lbs. Minimum 16M with 17M being an even better choice. I have compared a 14M Era to a 17M Contra and there is no comparison on low end IMO....not saying you need to buy a Contra. Shoot, I would put any 14SLE kite against a 17SLE kite for getting out of the hole assuming you have a nice big board.
The only way I could make a 10knot day work being 200+ is to already be on plane.....yet another great use for the stand up paddle board. Then yes, kite size really wouldn't matter....I could move around with a trainer kite.
On the other end, without her I can ride a 17M or a 12M just fine on a Flightdeck. I can get on plane with either size and go upwind. I do have to work the 12M though, and that's no fun. I have not tried a 9M, but I believe you, Scott, that it can be done and we are around the same weight.
I'm outtie and by the way, my daughter had a life jacket on and can swim. I am so proud of her. Before her 4th birthday she has surfed and kited with me. For all you parents out there with little ones, exciting times ahead. Jay, Adam, Rusky....
Where's the F'N wind!!!!