I posted the original picture you referenced with dimensions. i.e.
The shot is of original BL Au delivered door seals fitted to '78-80 FHC coupes. I am certain the pic is correct as I had three unrestored vehicles to compare the profile.
The lower outboard tube helped get a full seal, particularly around the upper rear section of the FHC doors.
The inner tube helped maintain a seal in the lower forward three-quarter section, e.g., where the occupant's heal tends to drag and tear the outer seal during entry and exit.