Try this. Use 2"x12"s x12' on edge about 10 boards wide and pull together by 1/2" all thread in 2-3 places evenly spaced. Before assembly tho. Layout a line on the bias that allows a ramp 4' long leaving a landing area 2' long. Cut the board on the bias line and you have two boards for the ramp 6'long. Repeat with however many 2"x12"s you want to make up your width. If you are so inclined; Makeup a wider set for the duals to rest on for the rear./Or just 1 wide set for front or rear use. The downside is these are heavy so you will want to store them close to where you work. A set of heavy rope handles goes a long way in helping to get the ramps in place and put away after use. I guess the upside is they aren't going to collapse under the weight of your rig.