Tonneau cover

I am presently looking for a cover that I can close the box down when my fifth is set up. I have looked at Access soft roll up,Bacflip G2 hard cover,Extang Encore and the Roll and Lock retractable. Does anyone have any experience with any of these or suggestions through experience. I am wondering about clearance.when towing. I have a 2500 HD GMC 6.6 box.
Thanks Bruce :trink39: