Hey Rocktor! You have the Mako King so you have pretty good planability. Let's assume you get the 8m. The King will assist you when the wind hits the lighter side of 8m conditions. But if Hatteras goes off and blows steady 30mph then I believe you will be overpowered and skimming along with that King flying your 8m kite high in the sky to survive. Plus though you can "hold down" an 8m in 6m conditions is it really fun?
Remember in April all our experienced riders, heavy and light, male and female were zooming to REAL to grab any 6m they could find. Slice had to borrow someone's 6m and he almost always rides a 14m! Rodanthe blew out of 6m kites like power generators blew out of Home Depot the day before Hurricane Sandy hit the East Coast.
But I've been to Hatteras several times in October and it never has hit the heights of my April trips so there is a gamble here.
So would a 9/7m quiver work or just an 8m? I vote you go with the 8m and try to get a guy in your house with a 6m who would loan it to you. In those crazy conditions trading on and off with someone to launch and land you is pretty cool