If you are truly trying to do fully planing carve jibes, remember speed is your best friend.
If you don't have the speed going into your carve, to stay on plane all the way around,
you won't complete the jibe planing. and instead will have to settle for a slow speed
step jibe when your board comes off plane.
As far as your board wanting to go upwind, it's most likely doing precisely what you are
telling it to do.
Are you all the way back on the board and in the foot straps when you feel you are planing?
Check that you are not standing slightly off center of the board (on the upwind side) and tipping/tilting
the upwind rail slightly lower than the downwind rail.
You board will go at any angle you tell it to, but now you are foot steering completely, and tiny little
changes in the side to side angle of your Futura 131 will steer your board.
Lee rail down slightly, and you will turn off the wind a little. Keep your board flat and it will go straight in
whatever direction you are pointing.
Tip it slightly to windward (lee rail higher than the upwind rail) and it will constantly want to turn upwind.
You are on a true short board now, and trying to steer with your rig as you did on your Fanatic will not
Yes, you can influence your direction some with how you position your rig, but once planing, and your rig
is raked back, it's all about the rail to rail (athwartships) attitude of the bottom of your board and the only way you can change that is with your feet and your weight.
Keep your weight over the centerline and you go straight (non planing).
Get your weight onto the rig (through your harness and harness lines) and even though your weight is
well off the centerline, the applied pressure from your weight will be through your mast foot which is
on the centerline.
Hope this helps,