This statement is coming from someone who has little expertise in aerodynamics.
The reason I asked the question is because my CT is about 2 feet higher the the F150 TV with a tonneau cover.
I am going to replace the tonneau cover with an A.R.E. cap. I am hoping the cap will help a little with the air flow. But I was also hoping that if I add a kayak or most likely a Thule type top car carrier to the cap, it would help beak up some the flat front air resistance I am now getting with the current TV set up.