First decision is 2, 3 or 4 sections, I just did three. Three seemed the best compromise of coverage and not wasting sections. It leaves a small section open on the bend between levels but my rational was that it let air pass through for less resistance. May or may not be true. The little bit that does hang over the bend was easily cable tied down after leaving it in the sun for a little while, it was quite pliable. I did cut a few very small notches out to make a tighter fit but not at the front. I just slid it up and left a straight line. it you want to go all custom there, you can make more notches but then you leave more open space and might need the 4th sheet. This was for a D1, a little shorter than a DII.