The 1/4" plexi should work fine, but the biggest thing with Ski's, is turning. If you just curve the front, and try to run, it won't steer very good. You need to figure a way to put a runner down the center of the bottom of the ski's. That way, when you turn, rather than the ski's "floating" on top of the snow, the runners will "grab" the snow, and turn the truck.