I was thinking that since the angle of my boat tail is so high for clearance reasons, I could make a piece of coroplast that hangs down at the desired angle and that is held up by some cable. This way, when it hit the ground it would simply go up and then come back done smoothly. I've attached a photo of what I have in mind.
Not sure if this would help or hurt aero due to the open sides , but I could probably find some sort of flexible membrane to cover this area.
Let me know your thoughts.