Wakeboard-size

I am gonna be getting one of the new slingshot boards that just came out for 2007 pretty soon but im stuck on what size/board to get. I just got an 05 malibu VLX, right now im not too experienced but will be riding pretty much everyday this summer.

I weigh 150lbs and im about 5'9". Im looking at either the recoil 134 or 138(softer designed for more advanced riders) or ther response 137(stiffer less advanced riders). thanks in advance.