If you wanted to use the corrugated plastic, and since it wont be one piece, my only suggestion would be to go the opposite direction. You said you wanted to start in the front and work back. I would start at the back, and work toward the front. Then you could overlap the sheet about 6-8 inches (or even more, to your comfort level), and it would look similar to roof shingles, then the air (while driving) wouldn't be able to get into the seems.
2015 Rockwood Mini Lite 2504S
2015 Ford F150 Ecoboost