The combined range of your gear is limited 'cuz that board is killing you. Believe it... haven't we already gone over this?
Do you know how much horse power it would take to get a crappy hull (covered in barnacles) out of the water on to a plane and stay on plane? A ton. Same thing with a little board. It takes a ton of juice just to keep it on plane. A larger board is night/day.
Takes hardly any juice, especially once you are up and going.

I only use one kite these days (a 9m).
I can ride it from solid 8 knots to almost 30, by just switching boards.
That's no exaggeration, plenty of guys see this all the time.

Yes I weigh less than you, but your board is far more important than your kite, as evidenced by Tom and I riding in sub 10 on 9m kites the other night.