With the typical wind being 8-12 knots you can not expect planing unless you have a good freeride/slalom board and a big rig of at least 8.5 m2. But even that will be challenging, especially before your skills have grown. Or then a Formula and a 11 m2 sail. But that also require skill to use well.
I think that you would benefit most from a Phantom 320. It is not a shortboard, and thus not as hip. But it actually is fun also when the wind isn't enough for planing. And it will in fact be just as fast when planing as a Rio or Funster. But of course, you need the same sailpower to plan...