Tough question, one I am struggling with too. I want a big kite as anti-skunk device, when my day at the beach arrives and the wind is less than forecasted. Problem is, seems we don't really have "light wind days" around here, where it is 8-10kts steady....we have highly variable 8-10 that will regularly gust to 15 or may suddenly drop to 0. So, it seems like if you get a big kite, it is either not steady enough to launch or you are often overpowered.
Life being about tradeoffs, seems to me you either chase that bottom end with a kite that can fly in next to nothing ... or you give up this 1 or 2 kts for a kite that can still be fun if the wind increases.
Right now, my project is a BRM Cloud 17m. I am learning about its potential ... and so far it is the former, takes very little to get in the air, but uncomfortably juiced at higher winds. I thought this kite would replace my 14m, with a perfect transition between the 17m and my 12m....but now think there actually is a gap there. I guess I may be keeping my 14m after all.
My prior project was an Ozone Edge 17m that I had briefly. It was no problem if it got a little windier, but I don't think had quite as good potential when it was really really light.
So....I guess the answer I am suggesting is to just get both.