i have found the easiest way is to have the plow guy make a big pile of snow. then carve one side flat, build ur wall ride on that, have it extend above to pile of snow. doubles as a qp
we nailed a 2x4 between two trees, and then we just nailed three 4x10ft (yeah i know theyre normaly 8 ft) pieces of ply wood verticaly from that 2x4. Also see if you can find a spot that is like a valley so the hill goes down and then up again and the wall is at the beginning of the up. That way the wall seems taller and it uses alot less snow. it worked real well for us. We just stalled and spun up onto the top we didnt slide the top like a regular wall but we didnt need to cover the ply wood with anything either and it slid fine. try and make the angle between 45 and 90 when your setting it up its reall obvious what angle will work best.