With sandwich construction there's a vertical sidewall between the edge and the flat top surface. There's no significant performance difference between the two. For recreational riding, the board's tip should reach somewhere between your collarbone and nose when you stand it on its tail. It should be just wide enough that your toes and heels won't overhang the edges. If they do, try a wider model.
Accessories can double that figure.
We recommend Fogdog Sports Snowboarding Store . Or, use our Snowboarding Store links to find other snowboarding equipment and apparel links. They contain support structures to transmit your leg movements to the board. Don't expect to ride efficiently or safely in a boot not designed for snowboarding. Most of these are made of leather and are comfortable enough to walk around in.