I use parallel thrusters on my wave boards -- the FCS G-5 fins work well, but there are lots others that will do the job too.
You don't want to toe them in because it will slow you down, although if you're JUST surfing the board as opposed to using it for light winds, you probably would toe them in a bit (not to the nose, but maybe a foot or two ahead of the nose).
I cant them outward 5 degrees from vertical.
You can sort of see what I mean if you go to our website, bottom of the kiteboard page where is says "more kiteboard pics", then look for the pics from Barbados of "Matt's #5 board". Sorry I don't have a better pic to show you.