Sounds like what I am looking for.

The Shoup one mounts on front curved rail wraps around post and drops  down to rear window ledge but requires drilling holes front and back which is something I would prefer not to do.

https://s7d6.scene7.com/s7viewers/html5/ZoomViewer.html?closeButton=1&serverUrl=https://s7d6.scene7.com/is/image/&config=Scene7SharedAssets/Universal%5FHTML5%5FImageSet%5Flight&contenturl=https://s7d6.scene7.com/skins/&asset=shoupparts/CC44%5Fis