Surfing Waves

Hi Peeps, I was wondering, I'm going to be painting my surfboard. I've read that you can paint the board with water based acrylics, which is what I plan to do. But should I paint directly onto the polystyrene board before glassing?

I cut out stencils and spray paint onto the finished board. It isn't as permanent, but it is very easy to touch up (I keep the stencils).