Get a stick: directional flex and/or shape and ride the fucker.
If it dont suite u get another and ride that one: pretty easy if you ask me.
what this guy says ^^^^^^
One of my boards is a 153 Gnu Carbon Credit (center rocker/flat from insert to tips). I weigh about 145lbs so I'm in about the middle of the weight range. I ride mostly in Hokkaido and in the deeper stuff it does not give sufficient float. I feel like I'm doing a manual most of the time and it's a real rear-leg killer. If you're set on going the Mervyn route, definitely oversize.
The board I use most for Hokkaido is a Nidecker Ultralight 158. It's directional, tapered, slight center-camber with rockered tips. Works great in the pow.