Have you got a link to the Thru-hiker thread, Jim?
Is the DWR you mention the DWR as the fabric comes (i.e. manufacturer's DWR), or user applied after making up the garment? I can see that it might bind better to the non-calendered face, but I wonder how it's applied; spray or dip? And, in a fabric so thin, can any DWR application be restricted to one side; might it not soak in to the entire thickness of the fabric?
[all questions intended as open: I have no pre-conceived ideas of the answers]