Shucks, I thought I searched real good for other posts on this topic before I started a new thread. I have the same question. What is the ideal shape? I have looked at a bunch of different production boards and they seem to have a sharper edge with the bottom surface being mostly flat all the way to the edge. Thin Rails with the rounding on the topside of the board. I am making a few plywood boards this winter. I won't know how they ride until it warms up though.