Same thing for me - 1/2 PVC tubing (with a crossbar in the middle to add additional support)... works like a charm and doesn't scratch too much. I also added weather strip grade foam to the inside edges to cut down on rubbing.... After trooping twice, I have found that the straps need to be replaced and re-worked - anyone have any suggestions?
Pretty much ditto, except I used 1/2" PVC.